I think you will find that your starting problems will be cured by replacing all of your big wires (ground straps, starter wire, etc.) with the proper 2/0 size (that's not #2, it's much heavier). The 4 gauge sold for 12 volt systems are way too small and will kill your cranking speed. Your wires should never drop more than 0.5 volt or they are too small. (You can test by hooking your voltmeter across them in volts mode and cranking) If your battery is being cooked then fix your voltage regulator.
I ended up replacing my generator (went south) with a self-exciting 6 volt alternator (Delco 10si with special regulator) and keeping my system six volts. Now it charges at idle, regulates perfectly, and is still mostly original. I can swap the old gen back in by just reversing the bracket and hooking the wires back up to the voltage regulator. It cost me a whopping $25.
