It's easy to install a remote regulator sensing on the Bosch regulator.
It doesn't cost anything. That way the regulator can sense/read
the voltage at the battery terminal for more efficient charging.
All it takes is one wire from the battery to the regulator and
and 10 minutes of soldering. I use remote regulator sensing,
in conjunction with the battery isolator.
But you wouldn't have to use an isolator.
On a sailboat, one has to closely monitor a
bank of deep-cycle batteries, (btdt)
but to do this in a westy would be over complicating things.
My original Varta starting battery lasted over 7 years.
If you want long-battery life and hassle-free charging,
just get a battery isolator with remote regulator sensing.
Totally trouble free hands off reliability.
My 02 cents.
Read about isolators and remote reg. sensing:
http://www.geocities.com/harald_nancy/
Harald
'90 westy