Some aggrement in this very old thread that base gaskets can be beaten about via lose head studs and therefore lose cylinders.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/198784-head-studs-how-sure.html

Not to beat a dead horse, just that everyone is obligated to do thier own reasearch and draw their own conclusions.

Out of the 24lbs or so of spec torque, I recall doing maybe 18.5 or so (starting at 10), memory is fuzzy it was seven or eight years ago.