RE: Delta Vortex build
Roary,
Thats a great question regarding the rearward placement of the main retracts, and I had spent many hours considering this vary issue. I had found several builds where Vortex builders had moved them back as much as 2", yet known of them reported any rotational issues. Mine are moved back 1-5/8" I guess ultimatly I can only answer that question on the maiden flight.
Mike