Sounds like you have enough to share
I can't believe that TST doesn't provide a small screwdriver in the kit, like they do the allen wrench for the locking screws.Especially given how difficult those battery cover screw are to remove without the tiniest of tools.
To avoid the pain as long as possible, here's a tip. If not using the trailer for weeks or more, and definitely while in storage, loosen the locking screws and back the sensors out past the point that they are pressurized. This turns them "off" according to TST, so they'll stop transmitting/using battery power. TST says the batteries should last a couple years. Mine lasted less than a year, and two died on the road in May. I couldn't find the right batteries anywhere, either, until I got home. So I replaced them all and bought a spare set, but have started turning 'off' the sensors after each trip...just one more thing to remember to do (screw them all the way back on the stem and tighten locking screws) before moving trailer again. Hoping I'll get a few years out of the batteries now.