That is a huge generator, so you can do anything! :)
My Honda 3000 will run 130a of non-PF corrected chargers before popping its breaker. It will run more amps worth if some of the chargers are PF corrected. Eg, I can run 150amps instead of 130 when I use my PF corrected 100amp charger and 50 amps of non=PF corrected.
So how many amps can the batteries take anyway? I like to use 33% charging rate as about the most they can realistically take and their internal chemical reactions can "keep up" (Mex might "clarify" that! :) )
So 600AH would be say a 200 amp charger. You might not find one of those! so just use a bunch of chargers that can do a total of 200 amps. make sure they are all about the same voltage in the mid-14s or higher, so they will all contribute their amps for the Bulk stage.
If one is of lower voltage by much it will drop out and there goes that much of your 200 by the way-side.
You have a 45 and an 80 for 125 so you need another 75. BTW make sure the 45 and the 80 are in boost using the charge Wizard or Pendant or Button so they will stay contributing when your 14.4v 75a is added to the mix.
I have a photo of four Vectors doing near 130a total off my Honda 3000 somewhere.
