I too have an Avistar which I'm looking to spiffy up. I like the tail dragger look and also the bolt on. I am very interested in the cowl idea. I will be watching for any good tips. As far as dihedral, i'm pretty much stuck which what I got because I epoxied my wings together and glassed them over. Maybe I can order me (or buy for cheap) another pair and build it with no dihedral.