@chilipeppermaniac - The distance between the center of the tremolo arm hole and the 'e' saddle won't allow a common 6mm nut with a 10mm hex.
You could also accomplish this with a small 'C' clip from throttle linkage.
THOSE things are of the DEVIL. BOING,,,,,,,,,,,,,,,, hey where did my clip fly off to?
I really like your fix, Robert. I see that you and I are of a similar mind in taking a mechanical thing and "improving" the final product to work even better than highly schooled engineers/and bean counting accountants make a thing.
For example, way back when my motorcycle was a few years old, I had literally kept it in my kitchen. After any ride, I would disassemble the hard to reach parts and clean them from the kitchen sink and wipe down the rest of the bike. However, I had trouble getting my tail light/license plate holder unbolted from the frame rails due to one bolt just spinning as I tried to undo it. From my observation, the "nut" amounted to a brass ferrule similar to your "bushing" and it was housed inside the molded plastic that was the light/plate holder assembly. The factory designers were counting on brass barbs or rough areas like those on your bushing to be the friction needed to hold the bolt, or hold itself as the bolt would be loosened.
However, what I think I experienced was a bit of electrolytic reaction of the dissimilar metals and thus the bolt was too tight in the ferrule to loosen before the ferrule started to spin in the molded plastic. After studying any ideas I could come up with to get the darn thing apart and then able to assemble reliably for the lifetime of owning the bike, I decided to Dremel/whittle away the plastic around the ferrule enough to put some vice grips on it. Once I got it all apart, I modified it and the other side the same way, removed the right amount of plastic needed to put proper nuts on each side, and then bought 2 Stainless steel locking nuts and now can use a wrench and Socket wrench to service the unit as easy as it SHOULD have ALWAYS BEEN from the GET GO.
Just for curiosity's sake, a few years later I would find myself at a dealer to look at the new models. The factory had changed the design on the newer ones. I bet you can guess why?