Hello Vinn,
I agree, the drivers must be sharpened to fit the slot but also finished off by flattenning the sharp end of the "Wedge" so that the flat part is in maximum contact with the bottom of the slot and the sides just about touching. It is a painstaking process that has to be done on each size of screwdriver.
I have bought Bergeon replacement driver heads rather than do it myself as although I can do it, I am quite lazy though I do "dress my blades" which is not a major bit of work and you usually follow the original design of the blade. The Bergeon replacements are provided in the condition that I try to emulate when forced into adjusting a driver myself. Most of my instruction on such matters was gained from a book "PracticaI Watch Repair by "Donald de Carle" under " Essential Tools" I would never attempt hollow grinding on a small, say .5 mm or any small screwdriver, quite frankly think that reduction of the metal available would weaken the blade considerably. In fact to be honest, I have tried hollow grinding only once, on a 2 mm blade under magnification and life is too short.
Having said all that I honestly believe that it is a personal decision and everyone should do what they want to do, if wrong decisions are made you soon realise and move on. Either way this forum is a great place for a frank friendly exchange of views that for an amateur tinkerer like myself has been really useful.
Cheers,
Vic