Hi Robert:
The CMX has two pads, and is over 5lb. I doubt you will get any better performance with the two cleaner cars, and then you have two cleaners to run and maintain. This may be practical if you also want to run multiple 'cleaning extras', but I don't think its practical to run two together, at least as compared to a single CMX.
When I used the HO unit, I typically used mineral spirits. However, I believe that stuff leaves a scant film, and in any case sends my sinuses into a frenzy. Since I have been back in 3RS, it has all been 91% isopropyl. It is safe, cheap, easy, and in my experience leaves no film. Many folks use other chemicals with a similar history of good results. However, I also see no reason to complicate things if something works, and isopropyl has worked well for me.
As above, this is only my opinion. No dogmatism is intended.