Battery Upgrade in Fuzion 371

[ChrisM]

My FZ 371 came with a single Group 27 battery located in the access compartment above the front right side landing gear. There is only room for one battery and to even weld in a second battery tray below it would require some cutting of the basement storage area. For this reason I decided to go a step further with 4 x 6v batts ( in series and parallel ) and a 2000 Watt pure sine inverter with remote on/off to power TV and other small electronics a few hours each night with occasional short high power usage by coffee pot ( brewing only ) or microwave. I plan to add a second transfer switch for the gen/shore power and inverter connections. I can manage the converter by shutting off the A/C breaker dedicated for that and manually switch the fridge to gas. I can run the generator to charge the batts during the day but want to be able to enjoy the other stuff quietly when late ( or early ). My questions regarding the battery install are:

1. Any issues with locating battery box, vented to outside through the bulkhead, in the basement next to inverter mounted to bulkhead and connected through 250AMP ANL fuse?
2. Do I need a "in-flow" vent near the bottom of the battery box?
3. Are the dedicated battery boxes worth the money or am I better off getting a sturdy tote bin with top and modify it?
4. I'd like to keep the 12v in the original compartment dedicated for starting the generator. Whats the trick to connecting things up this way so my 12v is still charged as it should be along with my new 6v batts?

I feel like this is my most ambitious mod yet and I like to know things are done the right way and so I appreciate the wealth of knowledge in this forum.