Stop in for a cup of coffee
one of the first real lessons I got related to fitting custom parts and what a PITA it is... Mike O'Connell (my you RIP sir!) who owned Mike's Speed in Belchertown Ma. was building an old panel truck and I would stop in to see him for advice on my car - he took me into the garage and showed me the truck and during the conversation said something to the effect of "the hardest part of any build is having to fit a custom made part - you have to take it off and put it back on over and over again, and it can really suck depending on the piece" - IIRC he was doing a rear end for it at the time - I still think of that whenever I am doing something that isn't going as quickly as I would like...