Yeah...chemo can be a bitch. My wife has had to get it every other week for two years now. Doc say's it will continue for the rest of her life, barring any miracles.

Are they still in veg? If in flower, a major trim-back of roots and foliage will definatelly slow growth, and if susceptable to stress...you risk nanners.
There's a link in my sig for (post-harvest) bonsai downsizing if interested. Works for ladies in veg, too...but you probably don't want to be so drastic.
The technique is a bit extreme...but works fine. It goes from a 5 gallon pot, into a 1 gallon pot. This technique also works in veg, if the need arises. I dropped a vegging lady and broke the 5 gallon pot she was in, a few months ago...only pot I had to put her in was a 3 gallon. Trimmed the broken branch, trimmed the roots, and gave some TLC for a week or so. She smoked just fine. :jointsmile:

Have you thought of putting the drainage rocks in the catch-trays under the pots, instead of inside the pot? Gives more foot-room for the ladies, and makes transplants soooo much easier. (no picking rocks out of the root ball)