Welp, I've poked, prodded; fitted & re-fitted that fiberglass fender that I made up and I decided that it just ain't gonna work. It
really does look like a yamaka, and I just couldn't come up with a secure way of mounting it to the forks without looking completely stupid and borderline unsafe.
So, I snarfed around ebay for a bit and wound up with a $25 generic Drag Specialties fender originally intended for a Hardley:
Once again, I'm completely remiss in actually taking any photo evidence of the process, but first I drilled out the rivets holding on the mounting bracket and welded up the holes and ground 'em smooth. Then, using some 1/4" DOM & scrap sheet steel I had laying around, made new brackets that mount to the stand-offs where the Gixxer fender would be attached:
I'm quite pleased with the results, if I do say so myself. Right now it's at the powder coaters for a layer of Super Chrome powder plus a layer of clear. Stay tuned for pics of the finished product.