I've done a bit more research. The tech sights look awesome, and while the company will not ship to Canada, Brownells does.
But before I start looking up old threads with hints and tips for Brownells success, HiCal has this one:
https://trueshottechnologies.com/shop?olsPage=products/ruger-1022-bravo-target-sights. Pros and cons:
- I wouldn't have to lose rail capability (I have a DLASK rail on it now)
- but this sight doesn't have to two apertures - just one, by the looks of it
- can't tell if it's plastic or aluminum... or how easy it could accidentally get bumped, and strip threads, or flip over.
Of course, HiCal isn't open today (or Tues), so I can't call them, but I'm going to watch Trueshot's youtube videos. Hopefully I'll have a better feel for it, then.
Edit: OK, all parts anodized aluminum. The vendor's video is 11 minutes, but answered all questions.
So: Results: If you want a rail, the Trueshot looks like the best option (unless you put the 10/22 into a chassis). If you like the smooth-top of the receiver, the Tech Sight looks like the better idea (flip peep).