You want the highest DCR that'll keep you just under the pinging point with regular gas octane with room to max out the dist curve. & you never want the SCR high enough that you have to compromise the curve. I would definitely achieve quench & with open chambered heads you'd need to mill the OC areas to square them up & go with KB plateau pistons. To ans your Q I'd say ~9.5 max SCR with quench but wait for more input from others