My understanding is a high aspect ratio sail is one which is tall and skinny rather than short and broad. The Balogh batwing sail looks like a high aspect sail to me so I assumed it was.

My rig is a monohull with outriggers. All of the boats using Balogh's mast, sail and AKA's and AMA's assembly and other similar setups all seem to sail well whether the unit (sail, mast, leeboard) are positioned in the front, middle or rear of the monohull. So using a clone setup like them, it's hard to see how the sail, leeboard position could go wrong.

: When you use a piece of blue tarp you can't get any of that. The tarp material has no stretch.

My understanding is that no stretch in a sail is what we are looking for so it will hold its shape. So Dacron sails are better then Nylon sails because Dacron has less stretch.

To build a sail similar to Balogh's batwings, you could use his sizes, which are on his site and then use the NACA foil shapes to get the shape and depth (chord) of the sail. Then white poly (don't know why this is any better then blue poly) could be used to make a cheap first sail. But better yet you could use Tyvek made by Dupont, which is a non-stretchable paper that is almost impossible to tear. It can be taped or sewed. You see this material as a wrap around new houses that are being built. Go to the post office and get a free large Priority Mail envelope. This is Tyvek. Try to tear it. Good Luck. If you should make a sail, post your results and pictures.
Cheers,
John