Update...

I found a nice Leupold M8 4x scope and installed it. After what happened with the Pecar I haven't got the courage to break out the torque wrench, but I've tightened the nuts by hand to "snug".

The Recknagel mounts put the scope at the perfect height, and they are very easy to remove and re-attach to the rifle.

Incidentally, that Krinkov turned out to be surprisingly accurate, though perhaps only because of my low expectations. I had no trouble hitting a paper target at 100 yards shooting it offhand (standing, no sling) using just the iron sights.