I always use brushes on wool rugs with the Cimex. I have been using this system for 34 years.
Use the 3807 or 4807 brush which is the softer brush but the 3805 or 4805 works well also.
If the rug is in good shape, it works great and does not distort, there is no torque on the Cimex like there is on a single disc swing machine. If you have any fiber slippage the Cimex will roll this into the brushes or leave it on the face of the carpet. Most of the time this is never a problem since most of the fiber slippage will come out over time or with vacuuming anyway.
It does a great job of lifting the pile and the agitation cannot be beat. Brushes just get the fibers agitated better than pads, IMO.
Couple of shots showing the brushes with the Cimex and the small Wool Rug to be cleaned.
Before Cleaning
After Cleaning
SA