You might as well just do it after the flush to get the stones out. The good thing about the oxy is that it also cleans the small intestines , the colonic just the large bowel.
Have you read Andreas Moritz website http://www.ener-chi.com under healthinfo read about the digestion liver/intestines. His book also talks about eating right. I don't know of you know Susanne Sommers book she talks about food combining, easy to do. Andreas follows the Ayurvedic sytem (5000 years old) also described in Deepak Chopra's book.
And the best one about digestion is the colon health thread on his forum //www.curezone.org/forums/m.asp?f=337&i=12699