Downtube does look to be easiest part! No idea on the butting on the seat tube and top tube, but why not leave a good chunk of top tube, and bring the he new top tube in in such a way to give it a GT triple triangle (this may not actually work give the angles but would be cool).
Downtube does look to be easiest part! No idea on the butting on the seat tube and top tube, but why not leave a good chunk of top tube, and bring the he new top tube in in such a way to give it a GT triple triangle (this may not actually work give the angles but would be cool).