I’ve been pumping for 7 yrs. also. It may seem like a long time, but PE is not a sprint, its a marathon.
I think the thing many people trying this stuff out don’t realize is that no specific exercise is perfect for everybody, and it takes a lot of time just to discover what works. I didn’t see my first real significant gains until I started doing other exercises besides pumping, and that was after 5 years of pumping.
I still pump because I believe it has its benefits, but I know now that it won’t do the trick by itself.
As for the HG issue, I have never used a gauge so I don’t know what vacuum I pump at. I’m pretty sure I’m pushing the limit though. I used to raise blisters because I would push too hard, but now I stop short of pain, and don’t leave the vacuum on for very long.
I agree with the original poster in that I also pull more length in the tube by applying more vacuum. An individual just needs to know what his threshold for safety is.