Just a couple of hours after my post this a.m. I got to see another 2L 
Type 4 in which the two plugs above the oil filter had been drilled and 
tapped and were awaiting fittings and hoses for a filter and additional 
cooler. I apppreciated Joel's and David's responses - one to know that it 
works well, and the other that it probably isn't necessary at this point. 
While out I managed to pick up a rubber boot for around the oil pressure 
sender and cut some inner tube material to seal around the oil fill tube.