The way it works is that if a player is listed as a starter (at any position) and also a backup (at any position), that player loses 5 minutes. You can actually get a single player over 48 minutes if they start in one position and backup two others, but in terms of training, there's really no way to leverage that effectively to do what you want to do unless you're training three positions. For example, if you were doing pressure for PG/SG/SF, the following scheme would get players A and B 48+ minutes in the three training positions, while the other player would get 36 minutes:
PG: A-A-B
SG: B -A-B
SF: C-B-B
(A would have 53 minutes, B would have 49).
That almost certainly isn't what you're looking to do, though. What I can say is any of the four plans you listed will result in A and B both receiving 43 minutes. Walkovers do suck.
