I’m only comfortable making sure the table’s clean & flat; the rails are equal; and the tip plate is same angle as top of the rails.(continued from above . . .)
This means that a pianissimo playing, the tone is basically a "sine wave" and as we crescendo, the harmonics rapidly catch up in amplitude to the fundamental till the reed starts to "beat" and then they grow in amplitude at the same rate. I have tried starting a note pianissimo and then making a gradual crescendo and can feel and hear where the reed starts to beat and the "transformation" of sound and feel takes place.
It makes sense that mouthpieces with wider tip openings require more air and input energy before the reed closes during each cycle of vibration and that this takes place at a louder dynamic level (greater amplitude) than it does on a mouthpiece with a smaller tip opening.
I’ve found a great empirical way of checking rails equal and tip angle is to use a single remote light source (the sun’s pretty single & remote!) and observe reflection on rails & tip as you tilt it. Sounds Heath-Robinson but is very revealing.
Here’s what I mean -