I use this calculator, it accounts for ring back volume, gasket volume, etc.
http://www.diamondracing.net/tools/
When I put in a 6.7cc piston dish and a Felpro 1016 gasket,0 deck, 92cc chambers, I get 9.7 CR. Maybe a little less if pistons are .005" in hole. (hard to see without deck bridge)
Use a cam with at least 230* intake duration and 112-114LSA.