My 17 year old daughter is 12 weeks post takedown and went from 20 plus BMs a day to 8-12 (ish). Imodium doesn't do much, metamucil helps but diet is the key I think. We can really see the difference when she eats bland compared to whatever she wants. No sugar, no dairy for her.
Also she just started going to a physical therapist who only works with people with contenence issues (bladder, constipation, diarrhea). She said she has had some good success with jpouch patients. She uses exercises and biofeedback. I feel like this is going to help and so does my daughters. She also has problems emptying completely.
It may be worth a shot to ask your dr to prescribe this kind of physical therapy. Good luck, it will get better!!