My short and sweet advice is this: Sell the bike and cut your losses. At this point, you're just throwing good money after bad.

I went through this myself with a custom bike, but my $5k mistake is just hanging on my basement wall. At some point, I had to accept that the bike wasn't going to work for me and no millimeter here or centimeter there with yet another fitting was going to change that. I felt much better once I decided to move on.