Main thing to remember is (everybody knows what comes next here :) )
"Your batteries work for you; you don't work for them"
My truck takes as much money to fill its gas tank as a battery costs, and I fill that tank often. So if you need to spend the same on a battery once every couple years, your wallet won't even notice!
Just do what you have to do, charge the heck out of them, don't baby them, just get the job done. But do take the time to equalize etc and try to keep their SGs at baseline. Forget "gentle charging" the batteries don't care about that. They have a "natural acceptance rate" in amps for the SOC and voltage so they take care of themselves. See that ugly graph 70amps on 220AH? That means you could do 140 amps on 440AH and get the same graph. You can't hurt them. Being "gentle" at low amps just wastes gen time (and gen gasoline)
