Pending availability of the Rivendell mounts, I mounted the Silver 2 shifters on Paul's Thumbies. It's not perfect, as the cable doesn't quite line up, but it's close enough for now. I tried Rivendell's alternate mounting, putting them on the bottom of the handlebars. It's a more natural thumb action than the standard. Still getting the hang of pulling the lever for upshifts in the back but overall liking this set-up.
The Paul's mounts mimic downtube mounts in having four orientations for the levers. If I understand Rivendell correctly, their mounts will provide more possible orientations of the lever, which would give a lot more flexibility. It'll be fun to get them & start playing around again.
Anyone else put them on flat bars? What has been your experience?
dougP