My take on it Jason (my personal opinion on it).

If you buy a totally original survivor car I think going to pains to make it correct is the go as all the stuff is there, just needs cleaning/fixing etc.

If the car is a bitza, why bother. Just do what Rod and Jennie did.

When I eventually get around to putting my Warwick Yellow GTS327 together it will be bits from all over the place, not worth the effort to do otherwise. However the Premier is that close to correct it is worth it to find the right stuff. Rims as you say is stupid, unless the difference can be seen from outside eg you'd want Canadian 6JK rims for a real early car as you can see the difference externally.