The 6v batts might be a little taller make sure you have room.
If you accidently deplete an AGM below 50% it might be more forgiving once its charged back up but I have found in the 12v models, that AGM and wet cells were both fine for my off grid camping needs.
What I do is carry a third 12v AGM battery that I run my 150w inverter off of when needed. I store it inside my toad and use it inside the rv on the floor out of the way.
That battery is charged with my solar system or my genny off a separate smart charger that accepts agm charging rates.
I use that for my 12v 40" tv that draws 5 amps :M.
That battery also operates my Dish Network recvr. off the little inverter. Doing it that way saves the coach bank for my stereo system , lighting, furnace if I should need it and vent fans.