Hey Patrick.
Thanks for coming back to tell us how you made out yesterday. I'll probably get the battery pack too.
I put the transmitter in a pouch that attaches to my guitar strap. I have Schaller strap locks on all my guitars, so it's easy enough to move the strap to a different guitar for swaps. But I don't tend to use the same guitar throughout a set.
How often do you swap guitars mid-set?