interesting to practically measure superior trainer effect. A friend of mine took a level 7 and at the end of this season will do some comparison with his former 4.
about your players (I expect you're training OD monorole, aren't you?), I can see some challenge in arranging a consistent training program.
Ariffin is not at all a bad player. BTW, his RB atrocious is a VALUE: my Scalambrieri has a very low RB and I estimated to save 15-20K$ per week of salary!! Not to mention how many people understimated his skill looking at salary...and he grabs about 4 RPG!
However, Ariffin deserves a robust series of monorole OD trainings. Without solid OD a player cannot compete. If so, that would affect Abdullah, who is proceeding well, but will need some some robust JS.
Something you could do would be to train both as PG's, alternating JR, 1v1, OD and PA with some well arranged, multi-seasons training program. If you want, I could give you some hints, as I have been training specifically PG's since many seasons ago.