That's just about exactly how I shoot in my yard, I have a camera tripod with a block of wood installed as a rest, then a small three legged folding camp chair to sit on....about the same size as yours. Would probably be great if I had more room, but in the yard it's just plain boring, besides I would like to round myself out a bit(no fat jokes intended, I know I'm already fairly round). Think I'm going to need a fore arm riser on my AA S400C before it's really comfortable, I suffer from long body short legs syndrome also:) Might have to mill up some fore arm riser hardware here in the shop this afternoon if I can get away from the computer, or, uh, I mean work:)