$700 USD? I’m looking at £750 on my end for a RAF.
We were talking about the stock jackets.
Is it the RAF/Irvin jacket you’re after, rather than the B-6?
Honestly even though the Aero is ‘better’, there’s a matter of comparative advantage and given that this is going to a Californian (who is presumably into the charms of WWII pilot wear but won’t be wearing the jacket all that often), the durability difference or shearling grade won’t matter all that much.
A stock size (or perhaps sizing down one, in a stock size) from 5* for a wartime jacket will give the desired ‘vintage pilot’ fit, and there are tons of very positive discussions of these jackets among vintage military jacket collectors.
I would also suggest that you consider the M-444. It’s a more versatile jacket than the shearlings people more often talk about, but it‘s not very widely reproduced. I think Five Star ended up doing it because a collector in the US sent him an original to study and reproduce.