Thanks for agreeing after three years 
Of course I saw what ends up in the fonts and I know the difference between hints and links (hooked hints), I am just trying to point out possible interface and workflow flaws.
A translation of PS Hints to TT instructions is obviously never going to work properly, it is a bit like writing a car manual by looking at a bicycle, but yes it is probably fast. When such a workflow depends on the negative value/direction of PS hints, you might have to repair the bug that I tried to describe. Maybe it is an unknown feature, but I have trouble understanding why the top of a T gets a negative hint direction, but the top of the O gets a positive value:
A minus value is not as good as a UI element to reveal the direction of hints as an arrow is, and the arrow is already there, another reason to ditch the minus.
Of course I totally agree with Jens that the hint position should be ditched in the label, it is not relevant for the hinting process.
Hinting only the first master is definitely NOT my preferred workflow. That master might be very thin or very narrow causing extra navigation, and hints might snap to wrong points that align with a stem in the first master but are very far apart in the black, which is actually very common. And then there are some rare floating hints, unhooked by lack of points, that I need to see and check in all masters.
You ask why I would like to measure stems in all masters with a hint, well obviously because hints need to be there anyway. That is just the most practical thing imaginable. I use them in the design process. Sometimes I fly through all glyphs looking at hint values just to check stem widths, obviously in any or all masters. And I use them for other purposes.
Your recommendation to first make a selection to measure stems is utterly unpractical, it would stretch the checking process to infinite lengths!
P.S. developers here made a Show Nicer PS Hints plugin for Glyphs that works in all masters, we think Glyphs can do better
