I may have said this before, check out brandEn's 'leak free top end' thread.
Good stuff in there.
I made a set of round brass spacers for under the cam tower pucks because the vesrah pucks i had were a bit too thin... but I decided to test my luck and order another batch to see if there was a difference in thickness.
The ones I got from cb750supply were nice and thick, and (along with permatex 2 smeared all around) allowed .035" compression between the head and cam towers, so I didnt need to use my home made spacers.