Re: thick or thin base gasket?
i made a spacer .100 thick and put it under the jug, then put the jug in a lathe and took .100 off the top. this raised the ports and gave very good over all power with a nice bump in lowerer rpm power. it's one of the best running engines i've built.
this engine also had an expansion chamber exhaust and porting.
put as thick a spacer under as you can without exposing the top of the piston to the intake port, then take an equal amount off the top of the jug.