I'm an insurance appraiser. Are you doing the repairs yourself? Or are you having a body shop do the repairs?

I ask because it makes all the difference in the world. The remainder of my comments will assume you are having the work done for you.

Your #1 priority is finding a quality body shop that has experience in resto work. This will not be a routine collision repair for any shop, particularly when it comes to the parts issue.

Almost all repro parts will need substantial "shaping" to get them to all line up properly. You need a shop that understands this, and an insurance company that understands this. And then, IMO, you need to let the shop and the insurance company choose your parts source.

If THEY choose the parts, then you are completely absolved from the extra time needed to massage these pieces onto the car, in the event that they don't fit perfect. And they won't fit perfect. Example: An insurance company may allow 3 hours book flat rate to hang a fender, but the shop may discover they need another 5 hours to get it to line up perfectly. Or maybe even another 12 hours if they have to build up an edge to close a gap or similar. This is the nature of repro parts.

So who is responsible for this extra 5 to 12 hours of time? Maybe YOU, if you are the person to chose and recommended the part source that was imperfect. (Side-note, you do not have damaged quarter panels if it is a front impact...you have damaged fenders.)

If the shop and/or insurance company sourced the parts? They take and/or share the responsibility of getting them to fit. I assure you that as an appraiser, MANY times when I specify a part source for a repair, and the part doesn't fit/rusts/needs help/etc, and I learn that the shop and/or owner did not utilize MY suggested part source, the insurance company I work for says "tough luck...you didn't get the parts I specified so we can't support them" and that costs the owner extra unnecessary cash. But if you and/or shop purchased the exact parts I specified, and they don't fit, it is MY reponsibility as an insurance rep, and the company I work for therefore covers any necessary extra expenses to make it right.

So put 100% of your research and time into finding a body shop that KNOWS how to fix these cars, and is willing to work collaboratively with the insurance company to get it done. And travel far and wide if you have to to find that shop. And then put them in touch with your insurance appraiser and let them get it done with very little of your input...including part source. A shop that requests your input in which parts to purchase, and where to buy them from, is a shop to run away from IMO...

If you're doing the work yourself? I'll let others offer suggestions as I acknowledge that I have no first-hand experience with body parts for these cars.