Rcimp,
I have a tough time remembering the backside of the ammeter too, but I'm pretty sure that + side goes to the BATT...this would make it the 'charge' side.
The regulator that has only three terminals..BATT, FLD and ARM can only be used with a generator. The regulator for use with a old style externally regulated alternator has four terminals...as you noted. If you have this style alternator, you need a different regulator.
The other questions will depend on what type of charging device you actually have.
Stuart
