I was wondering what you guys think is a good size for a small riding ring? We are planning our permenant fencing and I want to figure how much wood to order for the riding ring. I figured that I would do a small one... we really ride trails more than anything, but I'd like to have the ring for schooling/training if I need it. Plus, it would be good for a warm-up/cool-down area. So what would be good... 60' x 100'?