On our 4087 we have replaced the standard 3 x 12V house batteries with 4 x 6V (225A/H) Golf Cart batteries which are contained in 2 battery boxes forward of the Stbd engine next to the hot water tank.
There are an additional 4 x 6V (225A/H) Golf Cart batteries dedicated to the 3.1 KW inverter with the boxes mounted on a star board panel between the engines. The original plan was to have a crossover switch installed between these and the house batteries, but in over 3 years we have never found the need to go ahead with this. For convenience of moving around in the engine room, we installed a five eighths thick star board platform over the inverter battery boxes. The installation of the inverter was such that it will not try to power up the Water Heater, Battery Charger or Air Conditioning.
The engine start batteries are each 8-D's, and a Group 27 for the generator in the lazarette. No changes were required to the factory alternators which easily handle the added demand. (I think the std units are 105 amp)
During Summer, we usually spend at least a month without shore power, and tend to run the generator for no more than an hour each day, which is primarily to heat the hot water rather than needing to recharge the batteries.