Thom Fitzpatrick asks about provisions for oil flowing back into the
system. I am not quite sure if this helps but judging from what  have
I have heard on other lists the quality of the filter is important because
the better ones have a one-way valve that prevents oil from flowing
back down the lines (the filter is remotely located at the same height
as the old position). The cheaper ones do not have this characteristic
(I may be completely wrong on this)so as a consequence  that extra
half litre or whatever that is in the filter is not there at start up. It
does make a big difference in the time needed for the oil light to go
out.(3-5 seconds)).

BTW I uses a stock kit which many people have mistaken for ac rads on
old busses, few Vanagons have them (I think). More expensive adapters
allow you to screw the filter into the original position and have
external lines to a cooler.

Also the addition of the extra cooler was done not out of fanaticism
but because we wanted to get from CA to Toronto in the quickest time
possible and without incident up and down mountains. I had one bad
experience driving a Karmann Ghia across NA afew years ago and did not
want to repeat it. Lost 4th Gear around Winnipeg, drove with three
speeds to Calgary replaced the transmission for 300 dollars (I have
the bill somewhere...) after leaving Vancouver and returning to
Ontario the left cylinder worked its way completely loose dropping all
its oil. Tightened the four lower bolts (its all I could do in
acampground in Northern Ontario) drove back home and ran the engine
for another month until the no 3 exhaust valve started... tick tick tick.
That valve now sits on my desk warped and with a big chunk out of it
as a  reminder (they also make good wind chimes).... The trip was fun BTW.

DC