The motor cover is ABS so there isn't any RF interference, or at least it's minimal. On the non-drive side there is plenty of clearance and that's where all the wiring is, so I'm reasonably sure heat won't be a problem. A T20, T25, and some velcro is all you need. In the second photo you can just barely see a bit of white between the motor and the crank arm; that's the top of the Airtag.
I did wind up flipping the Airtag over from what is shown in the photos, so that the white side is facing out. I was able to locate/connect to the Airtag from a bit further away after I did this, presumably because the Airtag battery wasn't sandwiched between the radio and the motor cover.
There is also room in the downtube battery compartment, which would have been nice since it's a locked compartment, but CF kills the signal.
I did wind up flipping the Airtag over from what is shown in the photos, so that the white side is facing out. I was able to locate/connect to the Airtag from a bit further away after I did this, presumably because the Airtag battery wasn't sandwiched between the radio and the motor cover.
There is also room in the downtube battery compartment, which would have been nice since it's a locked compartment, but CF kills the signal.