As far as I understand, the only real differences between AGM lead acid battery and a typical lead acid battery is that 1) The AGM is sealed and 2) the fluid is in the form of a glass matt gel, and not a liquid.
It's still a lead acid battery with the same types of volts, amps, longevity, charge cycles, duty cycles, connectors, etc.
In extreme mobile scenarios (say a fighter plane that turns upside down) the glass gel would be superior because it doesn't expose the lead while moving. Maybe there's even a benefit for us while traveling. The other major benefit, and I think this is extremely important, is that you don't have to maintain it by adding distilled water, ever.
But your post seems to suggest some sort of benefit with regards to amp hours and I don't believe you'll notice any improvement there, whatsoever. So if a 100 amp hour lead acid battery is not sufficient for your usage, then a 100 amp hour AGM battery won't cut it either.