Jack i feel the guy 1. is too short to be a good SF, and 2. has pitiful ID which at his height will train UBER SLOW.
So, in terms of Roe obvious your first trainee, dunno who other is. but when you do 1v1 guards to boost DR, HN, etc. no problem for getting him reps. When you're not...
I can't say, I myself in single position training due to foul trouble and blowouts unexpectedly etc. am only able to train 2 players at a time in single position. But yeah.... I'd say keep working him at guard stuff when you can. he can be a solid 1 or 2. but is too short to be an effective SF esp considering his starting stats there.