I used a Magnum AGS in my system with a 4024MS inverter and BMK battery monitor. Really nice. I originally had the original version that just started on voltage. Don't get that one. Get the updated remote and the AGS-N. Why? 1) because it can be set to start on a given SOC%. No unnecessary starts when using the microwave or coffee maker in the morning and temporarily drawing down the battery voltage below the cut-in level. 2) it allows the genset to warm up a little before bringing on loads... because all of a sudden you have (in our case) a few battery chargers, a water heater, and the aforementioned appliances all starting at once. Our old 20kw Onan handled that with aplomb, but it was not good for it in the long run. 3) it also has the ability to program a cool down period with loads off before shutting down.
We were full time liveaboards who hung out on moorings instead of slips and anchored for weeks at a time while cruising. This was a terrific feature, made electrical management a no-brainer and we needed all those we could get on our fairly complex boat.
"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"