I wouldn't hesitate to change from 45 to 55 and no change in wire.
You need to know.....or remember that you may have a little voltage/amperage loss at 55 amps, but the amount of time the charger spends at 55 amps is so short, its not even worth talking about, and surely not worth pulling new wires. In 10 to 15 minutes you will see more like 45 amps, and another 20 minutes it will settle in at 35-40 amps for a much longer period of time.
So base your wire calculations on 40-45 amps, not 55.
But that's not saying that bigger is not better. And if it will make you feel better, go for it. All I'm saying is you will not notice any difference on generator run time.
And of course that is based on a PD converter w/ the wizard/pendant control
