I have after my engine rebuild in 2014 9:1 ratio pistons in my 3.4s which has been bored plus 40. My head was skimmed as well and although I have not done your maths my compression ratio must be quite high.I used the standard composite Payen gasket which came in a Gasket set from SNG. In the UK we have 95 and 97 ron unleaded at the pumps and I can run my car on either and not have any pinking or ignition problems. Our 95 ron is now 10% ethanol where as they have kept the 97 which is slightly more expensive at 5% ethanol so I tend to use the 97 Ron with 5% ethanol in my S Type with no problems.

 

I think you should be ok. I have used both the stamped sheet metal gaskets and the composite gasket and both work. The sheetmetal gasket is fussier about a smoothly machined surface on the block and head, and the composite gasket is more forgiving.

EDIT: if it makes you feel more comfortable, then go with the standard thickness composite gasket. That will drop the compression a bit and give you a little more margin against detonation. 93 AKI is good fuel though. As a general rule, engines require less octane to not detonate as elevation increases and temperature decreases. So Denver in January will need less octane in the same engine than Houston in July.