For absolutely no good reason at all, I decided to build myself a decent wheel tensiometer. I have a Park tensiometer which does the job fairly well but everyone needs a bit of digital dial gauge and fancy anodising...
It's basically the Jobst Brant design, roller bearing spoke rests, a linear bearing for the slider and a moderately expensive spring.
The next job is to build a calibration rig. Or to build another without the mistakes.