@JOG, Thanks. Since you mentioned it specifically, I went back to the S&W site... and eventually found the model with threaded barrel, etc. It wasn't obvious, doesn't show up until going through a "build it" process.
(I'm not at this point worried too much about potential "dot clutter." I take the point, but I reckon a red dot will probably stand out enough from the tritium. And probably the only time clutter might be an issue would likely be at night -- when a red dot would probably stand out even more.)
In the meantime, I've found an FN 509 Compact Tactical (509C Tactical) that's within driving distance... so I can go see how it feels.
One unstated requirement is that a candidate must fit my hands as good as or better than the pistol it might replace. Which in turn means I want to lay hands on examples before deciding whether/how to proceed.
-Chris
