Thick gaskets will lower your compression, but by such a small amount that it's really not worth it. Especially - as said above - when you kill your quench area.
Instead, you should consider changing your cam timing. Hold your intake valve open just a little bit longer and lower your dynamic/effective compression.
Dynamic CR
Interactive JavaScript to Calculate Engine's Compression Ratio (CR)
http://www.kb-silvolite.com/calc.php?action=comp2