Matt & Michelle
Thank you for the insight. I was not sure if you could modify the Valeo A14N118M alternator to install the external regulator. That is a great option given the ready availability of the unit.
I have been talking with Balmar, APS and Mastervolt. Looks like they all have a 2" foot small frame available from 28V/100-140A. However, to your point, all require the pully change to serpentine after you hit 100A due to belt slippage. It helps that the Balmar regulator seems to be programable to control the soft start up to 3 minutes to limit slippage and wear. But, that just seems like avoiding wear/tear that will bite me in the ass over open water.
All the vendors are scratching their heads on the pulley change with the dual alternator installation. I am not on the boat at the moment so cannot verify if their pulley setup will work, or how the Volvo is setup (single dual V or stacked/bolted dual V, shrouds, bolt sizing, clearance, etc).
I take your point on the size of the TMD and adding load. I have not done the loading calculations yet. Probably should have earlier. I imagine the parasitic loads have increased significantly given the age of the boat.
Thank you again for your insight. Much appreciated.