Need advice with new heads

if you have it zero deck now, go with a cometic .030 head gasket or if thats too tight for your liking...a .036
http://www.4secondsflat.com/cometic.html
With your combo I would shoot for 9.7, at 5000ft...you can get away with a decent amount on pump gas-less air density.

with a closed chamber head @5k ft, no problem...u could even go a lil more.