That's an excellent charger. I also use it on an Odyssey 100Ah Group 31 battery. It works great. Also, I believe it is on the Odyssey approved charger list. Another that I use on my Odyssey batteries is the NOCO, I forget the exact model, but it's about a 5amp charger. I remember looking it up, and the NOCO chargers were not Odyssey approved, and they have some information about this on their website. Something about the charge profile switching to float at a time not ideal for a deep cycle. That said, I use both of those chargers and they seem to keep the batteries healthy. I've been using them on Optima batteries, too, the new H6 (square design) in my Jeep and it keeps that one healthy as it sits for weeks at a time.
It's a great choice. You can use it on dual batteries, just make sure that you connect the batteries in parallel. If you have a smart isolator, that can vary depending on the isolator. You may have to experiment. The charge voltage will initially be high enough as it bulk charges, so it will trigger most isolators to put the batteries in parallel, but once it goes into float mode, it will likely isolate the secondary battery and only float charge the primary. That aux battery will eventually need some maintenance, so if you won't be driving for months at a time, this will start to matter. In this case, a dual bank battery charger may work out best.
If you have issues with isolation, though, you could always put the charger on the aux battery for a day or 2, it will fully charge it, then move it to the primary.