Wish you could get a cotton pilots jacket with a couple of pen holders on the shoulders.
The best I have seen was an old RAf flying jacket made out of the same stuff as they make rugby tracksuits out of. The bloke that had it said he could only wear if away from base and he had to be on constant guard of it being nicked.
And I know its not GA but if you could source some pilot shirts with a decent cotton mix. Not 100% been down that road and they are a bastard to iron. 70% or 80% cotton seems to be a good trade off.