That's no rabbit hole...
:sarcasm:
...why do I think I need this?
https://www.amazon.com/stores/PowderCoatingSupplies/page/6FC79FD2-0EE0-4A0D-BC57-2DA1DB08B14A?ref_=ast_bln&store_ref=bl_ast_dp_brandLogo_sto
Depends on how deep your pockets are. Lol
'Matching' red dots and magnifiers are nice, but not essential, as long as they line up properly. I don't have a brand preference, other than one that works with your sight easily.
QD, flip to side, or adjustable.
Let's start here; P80s should have at least 200-500 rounds shot through them before being considered "broken in".
Less that, you might consider a recoil spring, assuming your can has a piston.
What I would try, ask a Maine FFL if you could transfer your firearms to your daughter without physically transferring them to her now. In other words, is it possible to put the guns in here name? I would ask several Maine FFLs, as not all FFLs are created equal in their knowledge in the laws.
How many guns and worth are we talking about? All my guns are in my W&T, going to my daughter. I have a separate NFA trust, where my daughter is a trustee.