While the basic details have already been set out on this thread, ie GA and m/app procedure, climb to cruise and full STAR into the alternate, like BEagle, I would be interested to hear exactly what assumptions are made when calculating fuel for diversion.
Ultimately though, even a better calculated diversion fuel requirement could not cover the scenario where multiple aircraft are diverting from a major airport with poor ATC to a minor airport whose ATC is swamped. The amount needed in that case is determined by a pilot in receipt of all the facts at the time.
Finally, Dan, is it not the case that the amount of extra fuel is almost irrelevant if that fuel is burned before the diversion commences? Had these aircraft diverted immediately after discontinuing their MAD approaches they would have had more fuel at VLC. So it comes down to airmanship backed up by guidance from up on high as to when to commence a diversion.