I totally agree Keith!
My bug is inspired by the cars of the 70s, but times have moved on and I didn't build it in the 70s!
I run Beard seats as they are comfy and my back is shot, I run an modern Autometer Tach I like the way it looks and it works well, I run an MSD system as it does it's job well, I run Lucas turn signals as I think they look cool, I dechromed it because I like the cleanlines and don't have to polish trim!, I have a narrowed bean because I like the way it looks etc etc
Following 'the rules' I fitted 1 piece widows! - they are crap! I fitted a NOS Talbot mirror - looks awesome but can't see shit in it because I put it where it looks cool rather than so I could see behind!!
Great to be into period stuff, and if you have the cash and the time by all means build a period perfect 70s Cal Looker - but I say just build what is in your head for yourself.
Great if you have a 70s survivor, but if you are building a car now why not take advantage of progress!
Getting hung up on crazy period details will send your head daft, remember the real reason you are building your car - to drive it and enjoy it.
I worried too much about what people would think until very recently when I realised it doesn't really matter as long as you enjoy it!