There's no official info so it's all just guesses/personal experience from the way mm works. In general if you're matched with higher ranked players than before you're probably closer to rankup and vice versa. Though I have no idea whether the quality of opponents matter since you can have really wierd matchups with parties (generally the highest rank at the party is looked at and you can get something like 1 global, 4 silvers vs 5 not premade supremes).

I have accounts with ~1900 hours and ~300 hours. Both of them required around the same amount of matches to rank up each time. In my experience as long as you get winstreaks going you can rank up from any rank fairly quickly. You can even rankup during ties.