if i were you i would do an on/off protocol with both the CS and the probiotics. do large amounts of CS, then stop completely and do large amounts of probiotics, then the CS, etc. personally i have experienced CS killing off my intestinal flora, so i know that it can happen. and i wonder about taking them at the same time.
thats my opinion based on my experiences.
also you should take breaks from just about any powerful cleansing protocol like CS which is a very powerful substance. if you fast while taking the CS its much more affective. also, i wonder about taking 8 oz a day. is it really any more affective than 4 oz?