Frequency of Training for Imbalances

There are ton of great articles on this very subject the more I read, the more I seem to be confused, well more unsure about how often I should train to fix imbalances.

For example, my rear-delts are for lack of better term pretty pathetic. I’ve been focusing hard on supplementing my normal workout with those to better build these up so they catch up with the rest of my shoulders.

Right now I’m 1/2 through Waterbury’s ABBH II program which is great by the way. The workout is focusing on the bigger lifts like Deads/Squats/Presses/Pulls etc. I want to work in more supplemental exercises to resolve imbalances in:

  • forearms,rear-delts, bi’s/tri’s (I’ve got some poor imbalances due to lot’s of poor training habits)

What would the knowledgeable members here at T-Nation recommend for training the above? I am currently doing work after the main workout.

Should I:

  • focus on 1 group for 4-weeks, then switch.
  • try to combine more of the above in a given week
  • 3 days a week

I realize I need to listen to my body as well to see whether the workload is enough, not enough, too much. I’m looking for that tip to really get started so that I do it right.

I apologize for the long post and tons of questions but I’m really trying hard to figure out the best method.

Thanks in Advance