The hard part is where to access.
The tunneling and battery location is more of secondary thing that depends on patient anatomy. Just try not to move it anterior as it is a pain in the butt for doing lead revisions. I ask the patient how the sleep, bra/clothing, get a rough idea for cardiac risk as I prefer to keep the can down on the back in those.
I would love to hear more about the axilla implant but that seems like a PITA too.