What's the best way to attach a chest tracker (puck #4)?

I originally thought suspenders that cross on the back, then put a bolt through but that's just going to lock the tracker's position to my chest 99% of the time. I think a chest tracker is supposed to turn with the ribcage to match the avatar's chest bone.

I'm a guy so "lol use a bra" isn't going to work either. Any serious ideas? Maybe a repurposed backpack?