Your box is regulated. Don't worry about venting the batteries, as long as you follow basic battery safety precautions, your batteries won't vent. Your box acts kinda like a ground fault interruptor in household electrical applications. If the current goes to unsafe levels, the protection kicks in and cuts off the flow of power through the firing circuit. The box's display will then display a message like "Atomizer too low" or something to that effect. It's mech mods and unregulated boxes you have to watch out for. And the vape shop should tell you if a box is unregulated, as I'm sure they don't want to be responsible for someone hurting themselves. My friend's vape shop makes you sign a waiver when you buy an unregulated device and even goes as far as to ask questions to make sure you really know what you're doing, and you're not some random Joe Blow that's going to end up yet another casualty.
Just use identical batteries, watch for corrosion on the terminals and check on the wrapping periodically, and you'll be fine.
Cause right now im using around 70-ish watts.
