I really like this design, and both executions are interesting.
The first one looks like it is just primer gray, and it needs to be flat black, IMHO, weathered just like a standard pack. Use the acrylic paint in a clear pvc tube trick for the neon green tubing. I actually scored some st patty's day green flashing necklaces that could light up something like that easily. Maybe you could find a few of those, or keep you eye out for an upgrade next year. (Big Lots had them.)
You might want to do the bumper and various parts in semi gloss black to add some visual variety. Also maybe get some split loom to replace the rubber hose? The later one looks closer.. maybe use that as an additional reference?
Now let me use my critical eye to see what differences I can spot that might help them...
The only thing I see really off on both of these is the size... the cyclotron should be just a tad larger then shoulder muscle size.. but both builds used 9" cake pans, it looks like. Both upper portions extend past the elbow, and the diagram shows it ending before the elbow. That should also make them more comfortable to wear. Clay's thrower looks large, but its just because the gloves sort of blend in with the thrower colors.
I actually wouldn't mind seeing these make an appearance in GB3.. not as a main replacement for our beloved classic packs, but maybe as items being worked on by egon on a table somewhere, or maybe used in a test scene, where they are not yet ready for use and they need to revert back to the classic packs.
I haven't seen the comic either, but there is enough of the classic look there to be appealing.
I would think the weight would make them slip down the arm, without some type of shoulder harness cobbled up for them. Do they stay put when worn for a period of time?
These are one of the coolest things I've seen made for quite some time!
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