And when you get done fighting the screws because you don't own a screwdriver 20" long and you can't keep the head in the slot because of it, replace the screws with lag bolts and it is very simple to use a socket and a extension.
And put yourself a battery watering system on. I used Home - Flow-Rite Controls
available on Amazon. You can just gang the fillers into one unit and do the job easier.
Oh, congratulations on the new unit.