Speaking about seatbelt experience.
Having a little play in the seat belt has been a requirement in this house for decades.
I used two options:
1. Bought a gel pad that wraps around the seat belt and has velcro. It has a C-shape on the bottom side. Then you move this gel pad up to where it cushions between the seat belt and your chest. Making sure the 'c' cutout sits around your pacemaker.
and here is another version
These gave you a little 'ease' but didn't address the continued belt tensionning.
Helped tremendousely when my husband got his pacemaker until it fully healed.
2. My personal solution was to clip the belt in and then duck under the chest belt and but it behind my back. Yes, I know. Not legal, not smart, not safe. But vehicle either wouldn't start or dang warning bell kept going off. The solution stopped the ever increasing tension that never seemed to release on deceleration. It often seemed like the car was trying to cut me in half diagonally.
Eventually, I went to adding a 'stop' to trick the tensioner. I just put velcro where I wanted it to stop so I would still have easement in the strap but could wear it comfortably across my chest.
Now it seems the tensioner, like everything else, has a little 'give' and has lost some of its 'tone'. rotflmao
So, the belt tensioners and I get along pretty well now.
None of my vehicles had the lead on them like you folks have have/had.
JW