I attempted to set up the mixer configuration using 2 mixers to test the operation, only to discover one of them was DOA. It will take a while to get a replacement. I see one thing that may or may not be an issue and wondered what your thoughts were. The mixer(s) are going to respond respond to the amount of stick you feed in, right? E.g., if you give full up elevator, you would get 'full down' LE flaps. On take-off, you would 'level' the elevator which in turn would 'level' the LE flaps. It seems you would want down LE flaps until you got to speed? I noticed there is something called an 'Omni' by Vee-Tail which is a programable mixer- they're apparently not shipping now though. I guess my point is I don't think you'd want the flap configuration constantly changing. I could, of course, be missing something!