If I have to train jump shot or 1 on 1, but I have only three trainees because of one position training, I normally do this:
Buy allstar-perennial allstar 18 year olds with good skills except jump shot and maybe handling/driving. Include all three in training and sell them when you stop training on two positions.
I had a lot of success with this kind of training for one of my trainees. It's true I spent last season two position training also passing and OD, but anyway; I bought him at start of 14th season for 80k and sold him two days ago for 352k. Starting salary was around 4.700.