I must agree with dray, handling is very important for Point Guards
Passing and Handling would by my primary skills to train
the others are Outside D, Driving, Jump Shot, Jump Range,
I know you have already put him up for sale, but agree, better to train 6 players fully, than to get full training on 5 and half training on 2, and as was pointed out, it is very hard to get exact training for all players.
Also, remember that in 7 weeks or so you will be getting 3 new players in the draft. Likely that is you finish low in your series then you it is very likely that you will get at least Point Guard player that is much better then several of the current players you have. So as the season winds down, make room for those draftees. Also, at th end of the season there is a time of LIMITED training games,
And finally, welcome to Buzzerbeater!