Just got my Omron switch in, all works well now and wanted to thank you for the description and pictures.

My repair was complicated by my lack of soldering skill, I accidentally broke loose a chip of copper under the outer solder pad, and struggled a bit to scrape adjacent area down to copper trace to allow an electrical connection. In my efforts, I actually took the board out completely to see if the traces were visible on underside, that did not help. But I got to learn how ALL the tiny bits & scroll wheel get assembled. To be clear, if you break off the switch solder pad, it does not help to disassemble the mouse, just scrape to expose some copper and flow the switch leg joint solder toward that.

Afterwards, I was surprised it worked at all, as I had bunged things up pretty good, but the new switch fixed the “double click” issue and I’m happy!