Training in BB does not directly depend on the tactics used. So unlike HT where if you are training defenders, you will use a 5-4-1 or 5-3-2 (or a 4-4-2 or 4-5-1 if you actually are interested in winning) you get the same training in BB regardless whether you play 1-3-1 or 2-3. Your tactics will of course have an effect on the game results, which will in turn have an effect on substituions and playing time for training.
In BB, if you train more positions, the training per position is slowe. It is unknown whether the overall amount of training is less or more.
Because basketball is played with 5 players in a small area, all players will benefit from all skills to some extent. You can't have two players playing defense and two players playing offense, and the 5th passing the ball to them. In BB, a player without balance in his skills will be a liability.
Positions are also more fluid. A player who is a "SF" will play inside sometime and outside other times. So if you are concentrating mostly on outside skills, you might consider using a SF as your 5th or 6th trainee rather than always worrying about getting a 6th PG/SG into the scrimmage.