I think they should be marked on the fuse panel which are BAT and which are IGN ports, and you can always confirm with test light of course. Remember too, you gotta add your own inline fuses to those take offs to protect downstream circuit you're adding.
Yeah those TPMS sensors are nice when they work, but they don't all work the same way...some have to be synch'ed or re-calibrated with a tool, or scanner while others will just reset them selves after certain driving conditions are met.
On my C7, all I had to do was drive the car for about 5 mins at over 40 MPH (or something like that) and it turned the light off.
On my Denali truck, I don't think it even has the waning light/indicator that stays on.... it just comes up on the information center and goes out immediately after setting the pressure correctly. My last set of replacement tires, where was some attempt by BJ's tire center to charge me like a $30 fee for TPMS "maintenance/reset" and I told them to take it off, because I knew it was total BS and they just try to sneak it in on all vehicle whether they need to do anything or not.