You can use anyone of the three. The input requirement on the three ranges from 1100 to 1300 Watts, which means that a circuit even with 15A breaker will power them. If that circuit has a 20 Amp breaker you have more than enough.
The price differential between the three models is pretty small, the biggest difference is where you buy it, I've seen the 80 Amp model advertised from low of $190 to high of $245. My philosophy has always been that if a salesman is giving me an argument why I should pay a lot more for EXACTLY THE SAME THING he has already classified me as an idiot.
The advantage of having a larger amperage unit is that it will charge the batteries quicker when you really drain them down, although that might not come into play often since these have triple stage charging, high current, float and trickle and will maintain batteries in tip top shape.
There is another advantage of high current. You can plug the camper first into the campground power before you set the fifth up. This way the converter is supplying the power for the power hogs, jacks, room extension motors, etc. On my fifth everything is hydraulic, four rooms, entry steps and four leveling jacks,
even with four new batteries I often plug it in first to let the converter "help the batteries".
The PD units, because of their triple stage charging and particularly the trickle charge mode are also excellent for maintaining the batteries during extended storage periods. Cheap chargers have no trickle mode and basically will overcharge the batteries during storage. That's why you need to add water to the batteries after the camper sat for a while, overcharging evaporates the electrolyte.