[midnight911]

move the spacer kinda thing in the flange to the GKN flange. That way you don't have to worry about the bolt length. Now, I do suggest you look for moon plates and schnoor washers and use longer bolts to accommodate those materials.

I use very cheap EMPI moon plates for VWs p/n 875081. Fraction of price of a Porsche part. Schnoor washers and longer bolts were sourced from McMaster Carr.

When you buy GKN boot kit, they send you a small bag of grease for one CV. Not sure how much but perhaps you can get the amount from someone.