[Monster]

Michael,
You didn't provide some details for your application but I'll try to help you with some general info.
For a 3 wire application with an external regulator ,The "heavy" (Bat.+) lead should be 8-10 gauge and connect to the "A" connection of the Regulator and conect to the Amp meter (you may also conect an additional lead to the Bat+ side of your starter solenoid to aid in charging). The other wires from your Alt. are the "F" which is the field, and "S" stator both attach directly to the regulator .
Some notes, you should minimize the number of connections on the "B+" wire leading from the alternator to the regulator and gauge as these will cause resistence and may lead to problems (overheated connectors, melted insulation or worse). The "I" lead from the regulator is the "Excitor" and it applies a voltage to the switching side of the regulator, a 10 ohm resistor or an indicator light can be placed in parallel for this circuit which will serve as the "idiot" light to indicate a low charge condition.
Personally, I recently changed out my Ampmeter for a voltmeter, which I find to be more useful and easier to determine any charging issues.

note: Michael I just re-read your post and to answer your question "yes, the B+ normally goes directly to the Amp gauge then to the fuse block for distribution which includes routing to the ignition SW and to the B+ side of the starter solenoid. The addition of a lead from the Alt.B+ to the solenoid which I suggested will provide a more direct connection to the battery which will improve charging since the normal routing passes through a gauge, fuse block and SW all of which draw currrent and reduce the final output to the system.
hope this helps,
good luck,
Mike