What I noticed with most measuring instrucments out there is, stiction within the meter's mechanism and contact points between the instrument and the item being measured can really screw up accuracy/consistency of readings. I've encountered this on both expensive and cheap instruments. I always end up measuring things at least 3 times min. to get a close toconsistent reading, and even then, a 4th measurement might be well off from the first three which forces you to do more measurements just to get a measurement that I could trust is closest to actual. Yes, you can throw money at the problem by buying the most expensive instrument that might not have as much stiction, but you can never really eliminate the problem 100%. I think A tensiometer will just slow my wheelbuilding way down that it's really not worth it as the wheels that I build just using tone and feel have never "asploded" on me yet and they stay true and straight.
JMOs
Chombi