As far as the axles go, I would use the three tabs if you can find them. The original WS manual does not show them for the '68, as far as I can tell.
Here is a pic with some axle info. The CVs that used the gaskets have a recess around the outer perimeter to accommodate the gasket. My car has the gaskets and I don't think they do much good.
BTW, can't wait to see your oil tank installed.
__________________
Gordon
___________________________________
'71 911 Coupe 3,0L
outlawed
#56 PCA Redwood Region, GGR, NASA, Speed SF
Trackrash's Garage :: My Garage