The flax meal is used for the Muffin in a Minute recipe, I have never tried it personally. I know some here have stated that it makes them crave carbs more so they tend to stay away. I think someone mentioned it made them stall once. Some people can handle it though.
I don't really know much about the affectiveness of carb blockers, I've never taken them.
I think they recommend against Crystal Light is because it can cause cravings and you have to count each artificial sweetener as 1 carb and you are only supposed to have 3 a day.
That's about the extend of my knowledge
Hope someone else has more detailed answers for you.