I ran 42psi last year on the 42 with ARP's and the OEM head gasket with no o-ring. Never saw any problems.
If I could find some A1's I would be happy, but right now I do not have any. So there for they are not on my modification list.
I know Marco had a few sets awhile back, maybe I should get in touch with him again and see if he received and still has a set in stock.