Hey man, first off.... Great job on the fenders! Second, thanks for posting that up and opening my eyes on my own project. I initially wanted 'kafer cup' style glass fenders for my ride, but $ and international shipping were a huge turn off. That and it goes against every fiber of my DIY being to simply buy something. Then came your post... duh, why was I trying so hard to widen from the inside with all of the complex angles/shaping/excessive welding and hammering. Especially since I am in the process of widening some jetta fenders using a similar method to your fenders. I'm scrapping my first beetle fender mid stream and trying your method.
here are some pics of my short lived fender project (2hrs)
if these pics begin to clutter your thread, let me know and I'll pull em.
Inside edge trimmed off.
here the rest of the fender is with like 3" of extra metal, but 2.5" was what was going to be final.
I'll post up my own thread on my fender job once I get my project moved over to my new garage.
Thanks again for posting that up.