Donny: Thanks for the info.

I think I have figured out the geometry of the different A-frame stands. The Standtastik stand has a large footprint because the support (the back leg) attaches high on the front of the frame and goes back. The advantage while sitting is space for legs/feet/pedals. The disadvantage is a larger footprint.

The Ultimate Support Apex has the legs on the bottom and a center of gravity over the keyboard. The advantage is smaller footprint. The disadvantage while sitting is less space for legs/feet/pedals.

Isn't science fun?