Actually CTR pistons and a spoon head gasket, correct me if I'm wrong would have you well into the High 12 compression ratio range.

Keep in mind, the Civic Type-R may have a compression ratio of 11.5:1, but by using the same pistons, that doesn't mean that yours will also, you need to take into account the wrist pin height......

Also, when using larger dome pistons, and a thinner head gasket, you may run into piston to valve clearance problems. I'd look into it a little more if I were you......

Also, if you're running 92 octane, I'd say your right, and to be on the conservative side you don't want any more then like 12:1. I'd say, go mill your head thirty thousandths, that would accomplish what you want, for very little money, and without you having to go into your bottom end. Just remember to back up your timing if it's pinging, and keep in mind it may offset where TDC on your cams is.

Good luck, later!!

Aj