It does look like that switch will fit. A DA25a2 Mini with a clicky would be a game changer! It would essentially eliminate 2AAA penlights from contention. The extra output and runtime would make it a serious contender for Surefire type duty lights.
I know a few cops who don’t carry their larger Surefire or Pelican duty lights because of size. They end up carrying penlights for day to day stuff and keep their duty light in the car until they “need” it. We all know the light you have on you is the light you use when you “need” a light.
I believe if an ultra slim 2AA penlight were made that had a forward clicky and no more than two regular modes and also had a good clip, it would become the next Mini-Maglite. Make it cost about $30-40 and give it some good throw so it could be used as a tactical light or mechanics/electricians light and it would set the flashlight world on fire. I’m talking about selling in the millions like a Mini-mag not the thousands like 99% of lights.
I’ve never met a single person who owned a Zebralight, Fenix, four7s, Eagletac,etc. The only non-Maglights I have ever actually seen anyone use were either Surefires or Pelicans not counting no-name junk from Lowes or Harbor Freight etc.