Not a bad DIY fix in a pinch!
Another option that might be worth considering, if you don't mind an unconventional resource, is to find someone who can make things out of
Kydex. I've got a friend who is big into hunting and outdoorsy stuff, and has some custom holsters and knife sheaths he had made out of it. That's not my thing, but the versatility of the material gave me an idea. I got in touch with his "Kydex guy," and had a pleasant chat; Turns out Kydex can indeed be used for a lot more than the products people typically associate with it.
I've got a little all-in-one PA system I use for simple "DJ" type setups, with a small mixer that has protective rails on the sides. Those rails only do so much of course, but I thought they would make for convenient anchor points for something to completely enclose the knobs. I showed the mixer to the Kydex guy, who took a few measurements, then made a very clever little clip-on cover for it made from some sturdy, 1/8" thick Kydex. The low-profile nuts and screws used for "wearable" items stay well clear of the knobs, and the cover stays clipped on very firmly. No more worries about knobs getting tweaked (or worse, knocked off) during transport, load-in/out, etc:
Even without such rails on your Fly Rig, the material can be custom-shaped into just about anything. It may be possible to come up with a clip-on cover, or slide-on "sleeve" option, to completely protect the front of the rig. If you can get in touch with a skilled Kydex crafter in your area, it might be worth seeing what they can do.
Good luck!
