Don't tear it down. You can use your axles to test it.
Clamp one axle in a good vice. Slide the Sure Grip on and then the other axle. Use a good sized pry bar between the lug studs to see how hard it is to turn the axle. Seems like the manual calls for 100lb break away. If that's not right, someone will correct it.
And if it is not tight, don't trash it. I have fixed quite a few of them over the years even though a lot of guys say they are junk and cannot be fixed.
I’ll do that. Maybe a plate with the same hole pattern as the studs and a nut welded in the middle could allow me to use a torque wrench for breakaway.
You can just use a lug nut. 100lbs is not too much for them. Just bolt a wheel/tire on the axle that’s not in the vice.
The only down side to that is the weight. Getting kinda heavy out there with one end in a vice. The old shade tree test was if you can turn the tire with your arms the sure grip is shot. Then you disassemble and resurface (belt sander) the cones, but that’s a different discussion.
Yep, .030" to .050" off the small ends of the cones makes it almost as good as new. Such as that is. 
