Outstanding job, Greg! AFAIK, yours is only the second P-47 to fly, and it sounds like your test flights went just as well as mine did. I think I recall needing about 3 clicks of down elevator to get mine flying hands off. It's really gratifying when a new project does just what you expect it to do.
I experienced the same trailing antenna quirk that you described. In my case, it was with the 2nd Hellcat prototype back before I made it a regular practice to use a Deans antenna (I had one or two, but I didn't yet use them in all my planes). Not only does it fly better, it looks better without that silly length of wire whipping around behind it anyway.