JR and SB seem to be keystone skills. THey train soooooo slow though. I guess the best thing to do is set them up for an elastic effect.
I think this is the best way to go. I'm training a SF too, but it's his first season only, so I don't have much experience with it yet. The way I set the elastic effect with guards though is I train 1 on 1 for half a season so DR, HA and JS are at least 2 levels above OD, JR and PA. After that, I train OD and with that, I train DR and HA again so when I start with JR, the training is not that slow (pop every two weeks). I don't have experience in bigs training, but I guess it's a similar thing.