Manon, why SB>RB>ID instead of ID>RB>SB?
SB trains: SB, RB and ID
RB trains: RB and a little bit ID
ID trains: ID and some SB
If you start with SB, you will train three inside skills at the same time. After SB you switch to RB, which has already some training thanks to SB, and you get RB and ID skill ups. And in the end you finish with ID, which was trained with SB and RB. It's like a kaskade. If you go the other way (ID>RB>SB) you lose a lot of sub training. And Marin said it once: SB boosts the training of the other inside skills.