Depends on their age. If they're over the age of 25 or 26, they're basically useless to train.
Now that I look at your team, since 2 of your guards are ages 24 and 27, I'd try to play Macdonald and Zwintzscher at PG for 48 minutes and do 1-position training of Passing for a few weeks. 1-position training will get those guys leveled up much faster.