Or, you could use a cotter pin. Slip the cotter pin over one of the bead chain links, the eye of the cotter pin will fit between the beads. Put the cotter pin through the hole and fold the legs so that they won't interfere with the throttle stop. Anyhoo, this works on the Gen 1 and I put 110k miles on the bike with this setup and never had a problem.
If you are pulling the TB out anyway, you can take any ring or tab, then with one quick BZZTTT of an arc welder it's becomes one with the throttle tab and you are done.
BTW, grinding the bejeezus out of the screw head has happened in other installs.