I wonder how tight is tight enough when it comes to the jam nut? A torque wrench might be a good idea, but what are the torque specs for that particular nut? Just a few oz/in? You could look it up I suppose, but does that general spec. take into account a too hard (or soft ) screw? (insert your own dirty joke here )
I always go by feel, and it's been many years since I've had a problem either stripping or breaking a bolt/screw, etc.
Some people have a better "feel" than others...I've tried to tell and teach people and some get it and others don't, ya know?

I would think that you'd need to know the alloy of the screw, and then the proper temp. and ammount of time to "soak" it to actually re-heat treat them? I don't know, but I just used the screws they sent me and "snugged" the jam nuts down "about that tight"

Just 1 or 2 clicks of the elbow torque wrench? Or perhaps 1/32 of a grunt?