On my Sin I moved my 2 heaviest defence mods and enhancements and my 2 defence augments to my legs and belt (My legs are non-set) and I got a 2nd belt/legs(Thanks collections!) and put the heaviest Shield/Absorb Mods/Enhancements with 2 absorb augments in them.
Now all I have to do is swap those 2 pieces out. It helped that I had kept all the mods/enhancements I replaced along the way - all 72's no 69's. And am doing the same now with the mods for when 2.5 hits and I have to drop all B mods.
Why do you think you'll have to drop your b mods. Due to going away from self heals?