@Dogbowl it was just a question that you had a good answer to
Email the instructor and let them know the details. I highly doubt they'll let it go with a Transpac, but what they may let you do is use a standard hog harness and replace the shoulder triglides with one of these
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With that, you can easily make a chest strap from a piece of bungee or gold line and a bolt snap like many use on their sidemount rigs. Just tie it to one side, typically the left shoulder, then put a bolt snap on the other and clip it in. If you're going to get any approval for some sort of chest strap, it's going to be that one
That’s exactly what I’ve done with my chest strap.