I don't think tenting has anything to do with depth.
I only notice 'tenting' in a lady who gushes. After the delicious, maddening, pulsating contractions of the cunt during the early stages of her O, there comes a time when the vag actually loosens! What happens is the vag walls are convulsing - becoming firmed like a flexed muscle. That causes them to make a larger 'circle,' which pulls them outward, away from the mean old cock for a few seconds. That's convenient, allowing the gush (most or all of which originates IN THE VAGINA, not in the tiny Skene's Gland), to rush down the gorge and out the vulva, giving the buried cock a fantastic hot bath on the way out. (Ummm! I can hardly talk about it!)
I guess that might also result in a somewhat greater depth to the vag, but I have never noticed it, and frankly I think that would be kind of a stretch. (!)
All my gushing experience is by cock-power - I don't do the finger number when push comes to shove. Of course, I digitize other techniques!
Tenting may happen in ladies who do not gush (or 'squirt,' if you prefer); I just don't know about that.
Who has some more input on this?