Based on the following passages, in which Calvin explicitly mentioned textual variants, a few statements can be made:
(1) Calvin almost always accepted the TR reading without any discussion of a variant. He did this 32 times in the list of variants below.
(2) When he did discuss variants, he would most of the time, side with the TR
(5 to 4). a.
In other words, of the 41 variants, he sided with the TR 37 times.
(3) There is no point in saying that Calvin was unaware of textual variants, as he would occasionally discuss the variants and the evidence for them, arguing correctly about which MS traditions had them. a.
Nor were these brief references only for the major passages (such as the CJ, long ending to Mark, or the PA). Most of the time, his comments were on what many would consider minor variants, or those without much doctrinal significance. The implication being that he was aware of MS evidence for both significant passages, as well as minor ones, but most of the time, chose not to discuss them at all, accepting the TR reading.
(4) He knowingly sided with the TR, even when it opposed the Byzantine
Greek majority (at least 3 times--Mt 10.8; Rom 14.10; 1 Jn 5.7b-8), so one can’t say he subscribed to a Majority Text theory.
(5) He was aware of variants, even when there was little expositional difference. Many times, he would insert language to the effect that accepting either variant wouldn’t affect his exposition one way or the other. Even with the CJ, he said that even though he accepted it as genuine, he went on to state that his exposition would be applied only to the three earthly witnesses.
(6) The vast majority of the time, he accepted the TR variant; whenever he rejected it, he explained in the notes. This would indicate that he was knowingly using the TR as his base, and felt obligated to justify whenever he parted from it. a.
This is a rather tentative conclusion, but one that provides a useful plank for seeing Calvin as actively using and promoting the TR.
(7) In the passages tallied below, he explicitly accepted the TR reading 5 times, even when it opposed the Vulgate (three times), or opposed significant Greek MS evidence (twice); he rejected the TR reading 4 times,

once without explanation (Jn 8.59), thrice (Eph 1.18; 5.9; Jas 2.18) knowingly with the Greek minority and Latin.
Tally:
(A) Reject Vulgate, in favor of Greek Majority: 3 (1 Tim 3.16; Mt 6.13b; Eph
1.18;
(B) Accept combined Latin and numerous Greek MSS, rejecting “unknown anciently to the Greek churches”: 2 (Jn 7.53-8.11; 1 Jn 5.7b-8
(C) Saw TR reading as harmonization, in line with Alex; aware of omissions: 1
(Jn 8.59)
(D) Rejected TR 3 times (Eph 5.9; 5.21; Jas 2.18)
Mt 1.25 *
Mt 6.13b
For thine is the kingdom. It is surprising that this clause, which agrees so well with the rest of the prayer, has been left out by the Latins: for it was not added merely for the purpose of kindling our hearts to seek the glory of God, and of reminding us what ought to be the object of our prayers; but likewise to teach us, that our prayers, which are here dictated to us, are founded on God alone, that we may not rely on our own merits.
Mt 10.8 (raise the dead)—TR reading, *
Mt 18.11 *
Mk 9.44, 46 * (verses not commented on, from what I could tell)
Lk 22.44 *
Lk 23.34 (Father, forgive them) *
Lk 23.45 (eclipse or darkened) *
Lk 24.42 (honeycomb) *
Lk 24.53 (praising and blessing) *
Mk 16.9-20 *
Jn 1.18 *

Jn 1.27 (is preferred before me) *
Jn 3.13 (which is in heaven) *
Jn 5.3b-4 *
Jn 6.69 *
Jn 7.8 *
Jn 7.53-8.11
3. And the scribes and Pharisees bring to him. It is plain enough that this passage was unknown anciently to the Greek Churches; and some conjecture that it has been brought from some other place and inserted here. But as it has always been received by the Latin Churches, and is found in many old Greek manuscripts, and contains nothing unworthy of an Apostolic Spirit, there is no reason why we should refuse to apply it to our advantage.
Jn 8.59
Some copies have the words, And so Jesus passed through the midst of them; which Erasmus justly considers to have been borrowed from the Gospel by Luke
4:30.
Jn 16.16 (because I go to the Father) *
Ac 8.37 *
Ac 9.5b *
Ac 9.6a *, although a full paragraph discussing the phrase
Ac 20.28 *
Rom 1.16 (of Christ) * of this insertion in commentary
Rom 8.1b *
Rom 14.10 (judgement seat of Christ)
* (see his comments—he accepted the TR reading)
Rom 16.25-27 (placed at the end of Romans-TR) a few paragraphs on this, *

1 Cor 13.3 (body to be burned) *
Eph 1.18 (understanding)
18. The eyes of your understanding being enlightened. The eyes of your heart is the rendering of the Vulgate, which is supported by some Greek manuscripts.
The difference is immaterial, for the Hebrews frequently employ it to denote the rational powers of the soul, though more strictly, being the seat of the affections, it means the will or desire; but I have preferred the ordinary translation.
Eph 5.9 (of the Spirit, vs. of the light)
Calvin here accepted the Vulgate and Alexandrian reading (“of the light”): I wonder how the word Spirit (pneumatoj) has crept into many Greek manuscripts, as the other reading is more consistent, - the fruit of the light.
Eph 5.21 (of Christ, of God) Calvin accepted the Vulgate reading here (matching the Byzantine and Alexandrian as well) (IS THIS REALLY THE VULGATE
READING?)
But as nothing is more irksome to the mind of man than this mutual subjection, he directs us to the fear of Christ, who alone can subdue our fierceness, that we may not refuse the yoke, and can humble our pride, that we may not be ashamed of serving our neighbors. It does not much affect the sense, whether we interpret the fear of Christ, passively, thus,- let us submit to our neighbors, because we fear Christ; or actively, let us submit to them, because the minds of all godly persons ought to be influenced by such fear under the reign of Christ. Some
Greek manuscripts read, "the fear of God." The change may have been introduced by some person, who thought that the other phrase, the fear of Christ, though by far the most appropriate, sounded a little harsh.
Eph 5.30 (of his flesh, and of his bones) *
Col 1.14 (through his blood) *
1 Tim 3.16
God manifested in the flesh. The Vulgate's translator, by leaving out the name of
God, refers what follows to "the mystery," but altogether unskillfully and inappropriately, as will clearly be seen on a bare perusal, though he has Erasmus on his side, who, however, destroys the authority of his own views, so that it is

unnecessary for me to refute it. All the Greek copies undoubtedly agree in this rendering, "God manifested in the flesh." But granting that Paul did not express the name of God, still any one who shall carefully examine the whole matter, will acknowledge that the name of Christ ought to be supplied. For my own part, I have no hesitation in following the reading which has been adopted in the Greek copies.
2 Tim 1.11 (of the Gentiles) *
2 Tim 2.19 (name of Christ) *
Heb 1.3 (by himself) *
Jas 2.18 (by thy works, or apart from thy works)
Shew me. Though the more received reading is, "by works," yet the old Latin is more suitable, and the reading is also found in some Greek copies. I therefore hesitated not to adopt it. (The Latin reading being “apart from works”).
1 Pet 4.14 (on their part, but on your part…) *
1 Jn 5.7-8 (CJ)
7. There are three than bear record in heaven. The whole of this verse has been by some omitted. Jerome thinks that this has happened through design rather than through mistake, and that indeed only on the part of the Latins. But as even the Greek copies do not agree, I dare not assert any thing on the subject. Since, however, the passage flows better when this clause is added, and as I see that it is
found in the best and most approved copies, I am inclined to receive it as the true reading. Calvin’s Latin: video in optimis ac probatissimis fidei codicibus haberi, ego quoque libenter amplector