I would go for 60 or 75 minutes, sometimes when the opponent doesn't move fast, he's calculating the damage he will deal or that he will take, and most times since pro meta is different from showdown's, you need to change the sets to match the ou sets on pro, which can take time.
Also, when you find out you shouldn't stay against a mon, you need to calculate (most times) the damage you will take if you switch to another one, so i think when players take Time they just think wisely and not spam super effective attacks as they were NPCs
45 is way too few, you don't have the time to think, and 95 is way too much, specially if you face a time staller, you don't know if he's really time stalling until the last 15 / 20 seconds