builds a small frame in 140A based on a Delco 10DN, but has beefed up diodes, windings, and better bearings. It's wired for external regulation. I have one, if you can use the 120A, it'll be easier on the alternator. I would NOT use the 614 with ANY alternator without a temp sensor. I had an OEM Delco 21SI (I think) connected to a Balmar reg. Smoked it. Literally. In short order, batteries were at 70% SOC. Full fielded for a bit. No temp sensor. Dumb.
WRT the batt temp sensors, if you port the alternator output to the house (biggest?) bank, it should be representative enough to work. It uses the temperature to calculate the charging voltage as relates to temp of the battery. That calculation is based on the Slope (SLP) setting in the regulator programming. That value can be obscure, so do your due diligence in determining the correct setting, as a wrong setting can lead to chronic over/under charge problems that you'll blame on something else.
Get the temperature compensated float voltages from the battery mfr. and confer with Balmar to determine the correct SLP setting. It is poorly documented, so worth the time to talk to Balmar's tech support. They are very helpful.
I don't know the characteristics of the thermistor that is the battery temp sensor, I suppose you could reverse-engineer one, but I think a case could be made for using a single Balmar sensor on the biggest bank since that one will set the control pace anyway. Ask Balmar, they have answers, I have some experience, shaded by opinion.
There was another post weeks ago WRT the FFA setting. Very helpful. Mine was dropping back to absorb with any significant inverter load. Adjusting the setting allows the alternator to increase the field without kicking up to absorb voltage. Ahhh, that's
what was happening.
As others have said, the Balmar regulators are excellent, but using a "standard" preset program for your battery type is foolish. Gather all the information, create a table of your customized settings, including SLP, and then step through the whole programming sequence, advanced included. If you're paying someone else to do the install, ask to see their programming parameter table. If you get a blank look, you may not have the right installer.