hey all , i have just bought a 0.5mm trd gasket, so i thought when i take the head off to put it on i may as well get it shaved,

so
my question is, with the stock compression ratio of a s/t 20v being 10.5:1 how much do i need to take off the head to bring it to say... 11.5:1 (stock b/t ratio) or 12:1 keeping in mine that i have a 0.5mm gasket

or can i go higher than that safely??? coz if im gonna get it done i may as well go as far as i can

cheers, brendan