What inverter/chager do you have now and how many amps charging do you get when running the generator to charge the batteries? My 2000W MSW Zantrax will only put out 60 amps charging on the generator instead of it's rated 100A. I was able to lower the house battery rack so I could add another rack and double my house battery bank and this was before I decided to go residential. With 800 AH of batteries I have to run my generator 2 hours at night and one in the morning... mainly because of poor charging rate of my Inverter/Charger. Looked at replacing the I/C with a 3000W PSW one but my remote control cable is a four wire telephone and the newer I/Cers use a Cat 5 cable.
I would figure out how to double your battery bank and see how much charging you get from your I/C.