The angle, the back pad, the foot placement...they can all affect how you feel it. I say play around with it and see what works. I personally like a position where I can get my knees to my shoulders with my legs forming a 90 degree angle, and the overall angle practically pushing up, not out. Try it out, even switch it up in the same workout. I used to do a continuous triple set (read: death threat) where I did 10 wide, 10 narrow, the 10 toe presses for calves and started over until I was fried. Def. needed a spotter for that.