I have a leopard tortoise which is 6 and 5" the slower they grow the better just make sure you are feeding enough and giving the supplements like neutrobal and limestone flour (some alternate daily I use a little of both daily) also I like to use a UVB lamp but people have achieved good results without one. I always recommend they have access to a hide and a humid one at that (some humidity in the hide will promote smoother shell growth)
At the end of the day a tortoise knows what it wants better than you do. I use coco-coir from pets at home or kokosnot from Ikea its great. I also have some Timothy hay sitting on the surface in certain areas
