I think if you trimmed your number of trainees from six down to four, you would have 4 guys getting 48 minutes a week without much difficulty.
but, this would be a waste of 2 training slots. waste a lot of money.:)
IMHO there's no much difference in speed training when player plays 45 and 48 minutes. I think differences shows up when your player have much better other skill, and 5 inches is to little to affect for training speed so much.
You have the luxury of having 6 similarly-skilled trainees, so your minutes are evenly distributed. I think you'll find that if you sell, say, half of them and try to continue training the remaining half in tandem with new trainees, you may struggle to get the less-skilled trainees onto the court at all.
But that's beside the point. Others have already made the case for training the full 48 every week; what I'm more interested in is whether you've given thought to training the taller players at the wing positions (SG/SF) rather than PG/SG.
@ Everyone:
I'll ask again if there is anyone who has had extensive experience training Wingmen who would be willing to share their experience...?