Man, I always just swapped them without checking. Figured the gap was close enough out of the box. Seeing your 90k ones has me rethinking that, guess I'll start gapping them every other oil change or so.

The scuba setup really is not the problem here, it is the way you were positioned in the tank. At 38 feet you are basically floating sideways or upside down half the time, so of course the reg feels like it is fighting you, but that happens with a hat too if the angle is wrong. A harness trick helps more than people give it credit for, run the tank higher on your back and keep the first stage low so the hose curves natural instead of pulling, or throw a swivel on the second stage and it stops yanking your jaw. Surface supply is great until it is not, and if the gear is booked out then scuba gets the job done just fine, you just have to tune it. Plenty of shallow inspections get done on scuba every day by guys who would rather not drag a hose around a tank. You got worn out because your kit was set up for open water, not because scuba is wrong for the dive.