Wow I cant believe you built the frame! Havent followed the the whole thread so this was the first I had heard of that. Beautiful work! I would advise considering adding a strut from the area where the members that support the rear wheel are welded to the lower frame tube to the base of the "seat tube" in the area where the rack is welded. The rack is offering precious little support to the rear wheel frame work, so it is(rear frame) in a semi cantilever situation. I also dont know the tubings wall thickness so if you have a massive spec tube there its probably fine. The all up weight of this build will impose some pretty good stresses. Just my opinion and not trying to be critical, just something to consider. Once again beautiful work!!