i have had a base gasket blow out on a it200 (twice). i now use some hylomar on the base gasket (even though it's probably not spec'd for it) i also use some disc-lock washers (best invention ever. i use them on motor mounts too - no more retorquing every 8 hours.).. i've found no need to re-torque and haven't had a base gasket blow out since (knock on wood).
i don't think copper is the best solution for a base gasket...
07 gasgas xc300-94 duc 900ss-86 morini camel (2)-84 IT200-83 IT175-78 guzzi lm1-77 pursang 250-76 morini 3 1/2 strada-76 frankentaco pursang 200-74 frankentaco pursang 200-74 morini 3 1/2 sport-74 mz ts250/0-74 puch 175 (3)-73 can-am 175tnt-71 guzzi frankeneldo-71 ossa Stiletto-70 frankentaco sherpa s(2)-66 morini corsarino(2)-63 morini corsaro + many more