I also have colonic inertia and a tortuous colon, but I have small intestine, stomach, and rectal problems too so my case is a little different from yours.
For the
constipation I have tried Miralax, Milk of Magnesia, Magnesium Citrate, Docusate, Doculax, Senokot, Lactulose, Amitiza, and probably some others that I am forgetting. I am tube fed so my diet doesn't really apply.