Various gaps have been specified over the years and most people don't think about what they are trying to achieve with them or why and how they change. The general, if it is thought about at all, choice is the widest settings quoted. This is based on the assumption that they will close up with heat. In fact the opposite is true.
The 8V is very sensitive to valve clearance changes. All the Beetlemaps are built for 4&6 sure they will run at 6$8 but sub-optimally.