Certainly a healthy size! I'm new to russian torts, so I'm not going to comment on the health. It might help to include the age and sex of the tortoise? Do you have any specific concerns relating to health, or just curious in general if your tortoise looks healthy?
We found ourselves in the same situation. Our Russian is happy and healthy and grazes all day. We initially went with alph alpha pellots but soon switched to regular ol' organic top soil for like $1.99 a bag.