You can source elevator bolts from McMaster-Carr.
About 5 years ago I was running one of these clutch stops with the impression that it would make me smoother driver. However, that was not the case; I have found that my shifting is much smother without the stop, and I would imagine faster and safer for downshifts. Reason being is that the time it takes for me to fully depress the clutch pedal and release it is the time required to rev match the engine for the next gear change. One can of course rev match with the modified clutch stop, but it requires one to pause for a moment with the clutch in, I found this hard to repeat. Without the stop, I simply press and release the pedal as fast as I can and the required time is just enough to rev match.