May I just say, I'm not tall, nor do I have large hands. I have always played a 7/8th sized instrument (except for an occasional concert with my carbon fiber cello). Thanks to a very patient luthier, Curt Bryant, and good strings, I can easily have a large enough sound.
As the teacher of many petite cellists, I feel compelled to say: you do not need to try to play a large instrument. What you lose in agility is far worse than any gain in volume. I see too many people with smaller hands playing at a great disadvantage, not to mention possible and real injury, by trying to play large cellos. It's not always a simple question of hand size. Some people are more flexible and can get around a longer string length. It's ale, length of arms and shoulder width. One should not struggle to play the cello like someone hanging onto the mast of a ship in a raging storm.
I hope teachers will join me in helping students to choose cellos appropriate for them. Here's to calmer seas for all cellists!