Very interesting on Lactobacillus Rhanosus GG. What was the specific impact you had seen with this strain? I have a bottle of this strain but I haven't tested it and it might have some additives in it, I will check. But, I do remember reading that this is one of the strains beneficial for UC. S. Boulardii I am planning to test as well.
Saccharomyces Boulardii is especially useful while on antibiotics because it is a beneficial probiotic YEAST, so it isn't destroyed by antibiotics.
Hands down, my most effective probiotic was Lactobacillus rhamnosus GG. But that was several years ago when it was relatively clean without any additives. Now it no longer works for me probably because they added junk like maltodextrin and titanium dioxide.
Same with VSL#3. It used to work fine before they added junk to the ingredients. Lactobacillus Reuteri (NCIMB 30242) is in my signature and it seems to help but not as well as the probiotics previously mentioned before they became adulterated.