As I understand it, the training speed manipulations based on big/small have nothing to do with the position you train players in. Taller players will train skills that are related to outside players more slowly regardless of the position that you train them in and vice versa. That being said, the position that you train certain skills in does impact the efficiency of that training. I don't have the exact numbers down to memory but it is best to train any single position skills eg Pressure for OD in their single position, in this case PG. Training Pressure for PG/SG or just SG, SF etc will impact the efficiency of this training. For trainings like 1v1, changing between Guards, Wingmen, and Forwards also slightly alters the skills that are being trained. Training simulators like Coach Parrot or the one based off of the USA offsite have much more exact figures for exactly how each training type and position will train players of certain heights. But, in general, tall players train outside skills slower than inside and vice versa. Players with extreme heights, tall or small, will train inside or outside skills respectively faster as well.