Since making & having the side panels upholstered two years ago, the spare tire side didn't fit flat & flush with the fuel tank panel.

To tackle this job, I removed one staple & measured it at 1/4 of an inch. I just happen to have two boxes of these staples.

So I was good to go with my upholstery adhesive & an ultimate set of tools. 

The short story, remove staples, peel back the 'elephant skin', scribe to other panel, cut, test fit, glue, staple, trim & done.

Such a satisfying job.