The problem with those two verniers is that the wheel mech can play up, even in the short term.
I use my normal type everyday and you soon get a good feel for the clamping of the jaws.
If i doubt myself i calibrate mine againt a 1" slip gauge or a 2" slip just to get the "feel" about right.
What i would say IF you can find a pair with a valid calibration cert then they could be a decent pair.