So I didn't like how my fuel filler came out. It's not bad, but it could be better. So I scrapped it and started over. The thing that bothered me to most was not being able to get a perfect circle recess. I thought about it last night and had an idea on how to make a perfect circle. After work tonight I cut some scrap 1/4" plate and made a pivot point. I'll refine it later for infinite adjustment for up to 14" circles with a slot and a carriage bolt.
I'll update this again this weekend hopefully with the redesigned filler mount.