I am running it in a WDK Envy and whatever battery hold downs came in the hull. Shorai offers 4 or 5 diff case sizes, cant see why you couldn't find one that fit.
I was running a lfx18a1-bs12 which was quite a bit smaller, but i ran the battery down while sorting out mechanical issues and it never quite got back up to full charge on the skis charging system. I bought the Shorai charger and attempted to hook the cable up with battery still in hull (buried in back right corner), didn't get the connector in there straight and bent one of the terminals into another terminal and it shorted and caught on fire. I replaced it with the bigger battery because I had the room and the extra lb wasn't a big deal.
I read through the literature that came with the battery and charger and you can leave the charger lead attached to the battery at all times, so I sealed up the charger lead and hooked it to battery and installed battery in ski. No the plug is easy access for when ski is in storage and i can plug it in a used the charger to maintain the battery.