most factory make a best tone strike for the treble, but then the 1st bass is just adjusted so the back of the sharps is the same distance from key cover than note 88
You cannot decide the strike line with the hammer gluing distance, quite the opposite in fact, as the string's plane is not level, having the heads straight will make the strike line vary a little (noy on a Yamaha indeed)
a neater way is to use an elastic thread, installed under the strings; but it is common that the strike line can be considered straight only up to note 49, and tweaked above in the last 2 sections for tone reasons, it may depend of the piano and the model)
Basic formula imply a fixed strike ratio up to A49, but real world show different approaches, all playing around the 1/7 to 1/9 , but particularely on small models the ratio can even be higher so the piano have enough partials present;
ALso common is a point just near of 1/8, then the small moves of the action in the cavity produce more differences that if the strike where 1/8 from the start.
Anyway, I find more astute to verify my strike line on the models, then the reamer is used to play with rake in some parts, so the line is respected (not really important for the line, in the basses, but rake is changing the dynamic of tone.
Also, just to facilitate things, look at the 0.5 to 3° strings plane and think how you will get your hammer 90° from that
check in Reblitz
or in availeable documentation ... the schools about that may vary from continent to continent and from factory to factory, On a Steinway you are advantaged with the supple stack , hence the one size only heads used.