I read up on the Fiber Choice tablets, and I actually can see where it may be beneficial, as long as they are the sugar free version, because I do not see where it contains any bran (which contains phytic acid-a mineral robber) in the tablets, but inulin which can enhance calcium absorption. Flax seed capsuls are not like taking real flax seed meal or flax seed oil with lignans.
Now, with regards to Gary's bulky stools. You need to understand that before people heal, they often feel worse. In other words, if you are working on healing the bowels, which is vital, there is often a period where things slow down or speed up quickly. People that are the most ill, have constipation during healing crises (which are necessary to healing) due to putrification or gunk being lifted off the lining of the colon and moving to the center--clogging things up. This is temporary.
It is essential to be drinking plent of water to help loosten stools and flush out toxins. Those natural fibers you mentioned are great, as well as completely switching to 100% whole grains. People whom I've consulted with generally only notice benefit when the utilize the correct supplements to heal the bowels, and make the necessary dietary improvements (eliminating enriched or white flour and sugar-and other sweetnening that feed yeast). Also, by swithing to 100% whole grains, you will automatically be getting more fiber which is extremely important for the healing process.