Our testing is going to be conducted doing like 100 jumping jacks with the pack on and doing some dives as well. Then we will open it up and see how messy it is.
We are currently working on the backing plate design and also seeing if we can run both the marker and the pack off one air source. But this may prove difficult as the marker is the major requirement for air. But we are working on the regs to do it.
In the first version I did. I used a rubber foam tape and lined the inside of the hopper, it reduced the noise of balls moving around a lot, however the second version, I left out(needed the extra space for more balls). The pack casing keeps them fairly quiet, however, if you are worried about the balls breaking, don't be ..... they are quite hard and I run with the pack on and not one break! .... also because I have all of the balls and air for my marker in the pack, you don't need to carry any pods or air bottles!
I have warp feeders running the ball loading system so the air bottle is for the marker only! ..... I'll take some pics for ya all and post them ASAP!