At the end of the day i think it has to be LIFO. Surely it doesn't matter if pilots are just passing checks by the skin of their teeth or not, if they pass then they are good enough. Same with promotion to the LHS (and demotions, redundancies etc.), it shouldn't be picked from a list of the best,it should be seniority, if they pass the command course then they ARE good enough, end of story.
LIFO is the way to go regardless of age, sex, creed or colour (fleet, type etc.).
Wingman