I think a second oil cooler can do no harm.
remeber that the original VW only generated a small amount of power and
cinsequently did not need a lot of cooling.

If you want to drive at the new freeway speeds (highway 5 has a 70 moh posted
speed limit) and go 75 for hours on end a secind cooler may be good. I have
one on the side and it seems to help. People do put them inside and I do not
think this is good as it will pre-heat the cooling air

whatever you do will be better as long as it stays intack and does not get
wiped off.
sam 70 westy with cooler