Zen,
the oil filler
You can fill the oil by using one of the holes for the oil breather in either head. It will take longer to fill though. When I get my NOS case ready to build, I will bore out the filler location on the pulley side (bottom right) and fit an oil filler adapter tube there.
plumbing for the external cooler
I'm going to use a Mesa Cooler with fan under the rear parcel tray, with an oil cooler adapter off of the stock oil coller location
sealing tin (has anyone tried the OPP btin with a FAT shroud?) Not sure about that one yet... but will conquer when the time comes
linkage (through the shroud behind it, how?)
I'm trying to find a linkage like the one shown in Keith Seume's book... Custom Beetle Handbook, on page 81. It is a bell crank style... no hex bar...
So far I have less than $600 invested in the FAT shroud/Porsche alt setup....
I'll do a tech article on my install during the winter.
Sandeep