I tried using simple background pictures in my QTVR, but the file size jumped by 800%!!! So I rather abandoned that approach. As for the shiko dachi, your illustation makes sense, if the person only has one leg, but with two legs the dynamic is different. It's the right angled position of the legs that provides the stance with its stability. It essentially juxtaposes the two feet at oppositer corners of a square. Maybe I didn't pose the figure well enough to make that clear. My understanding has increased considerably since I did those models, and I noticed a few bits that I should redo. Having said that, it's not a stance designed to be held for a long time - you pull someone down with it then move off, or you sink into it, then lift someone. You don't have to have balance, so much as tension.