32 Volt Options

To follow up from an earlier post, I have recently re-wired most of my starting systems (batteries, starters, solenoids, alternators, etc). It was pretty old, corroded stuff. It is now clear that the batteries, while only three years old, are shot. I have an old ferroresonant charger which I left on continuously. After some research I believe this is what killed my batteries by overcharging. It jives with the evidence, cracked cases, constantly low electrolytes. For anyone familiar with 32 volt systems, can you recommend a charger? I found one at Fisheries Supply, Newmar PT-32-25W. I have twin Detroit 8V71s. Also I need batteries. I can simply replace my 4x8volt Dyno banks (5T) but am curious about AGM options, haven’t found a 5T equivalent yet. There is a 4x8volt bank for starting each engine. In addition some house stuff is also run off these, lights, pumps. 

Finally, an electrician has suggested I could drop in 3 12volt batteries, and everything would just “run better” on 36 volts. Has anyone done this? I am skeptical. Would batteries get charged properly?