James,
Hang in there. You are not alone.
I was working on my W.12 cockpit. I could find no references but I was determined to do as much detailing on the fuel tank as I could. I saw Bertl's build of the W.29 and figured the fuels tanks had to be similar, so, assumed if I made mine look like his, I'd be OK. And remember, I am the guy who crows, "don't make models of other people's models". So, I cut out a little dial face for what I assumed was the fuel gauge and found an instrument decal the looked right and went through all sorts of issues getting it mounted, etc. Finally, it looked out of scale but I figured it would do. I was breaking all my own rules, but, I figured it would be OK.
After going through all of this craziness it was only THEN that I noticed two little squares with numbers on them smack in the middle of the WnW instruction book; Sir Peter had been kind enough to provide the correct decals and correct sized fuel gauge right from the beginning.....I do not know how many times I looked at that page before starting the build and during the days I've been working on the cockpit, but, somehow, I never saw the indication for the decals. As my wife said, "well, honey, they're outlined in blue big as life.....how could you miss them???" Thanks, dear.
Justin's fix sounds pretty straight forward. Go for it, take your time, relax, and enjoy the build and you will find that your slump is over.
Vaya con Dios.
Cheers from NYC,
Michael