Thanks, J. Your thread was indeed the one I had in mind. Since I didn't say it then, I say now: that the drop-bolt you fashioned looks terrific--much better than the one on the Olmo. Really nice work.

I'll take this opportunity to add one more drop bolt to the mix. The one below came on my Ron Kit/Speedwell. For whatever reason, there is very little clearance between the brake bridge and rear wheel, even with a 700c tire. So little clearance that a "riser-bolt" is needed. What is interesting about the "riser-bolt" is that it has two grooves for the caliper spring--one for use as a "riser-bolt" and one for use as a drop-bolt.

Riser-bolt:


Drop-bolt: