According to Cambell-McBride an adult needs to take 15-20 billion bacterial cells per day for 6 months. This is a very large daily dose. This would be 8 pills per day of the Bio-Kult which has 2 billion per cap. I am up to 6 per day so far.
She advises to take them after meals when stomach acid is bound up with food.
Can I ask why you think the problem is in your colon and not the small intestine?
On page 327 she recommends an enema for constipation containing 4-5 billion strength probiotic with predominantly bifidobacteria species. She recommends a pure probiotic powder for this. Not sure if this is your problem or not.