Everything is looking AWESOME so far!!!! Feel free to operate on the pink pack I sent you, these will be replacing it
I was thinking maybe after you make the cutout for the magnet to sit in you could fill in all the gaps on the back of the pack so that it's all one smooth surface.
Also do you think there's a way to have the hose enter the pack on the bottom rather than in the middle of the cyclotron? I don't really know a good way to keep it in the pack without the knot that usually gets tied in the middle of the pack.
My one final suggestion would be to dremel off those clips that jut out the side of the pack, they were only there to hold on the old thrower.
This is already shaping up to be a great build. I think a lot of people will want these once they are finished. It's a stellar upgrade to those old RGB figures. You Sir, are a trend setter