How long it takes for something to reach the colon depends on your transit time and what is digested. I guess if you have diarrhea your transit time might be very (too) fast. Also if you take the antifungals alone and not with food, maybe they reach it sooner? Hard to say.
If your digestion is weak and you are not producing enough enzymes for breaking down fiber that already can give fiber intolerance issues. Not sure it always would indicate SIBO. And gas can also be caused by Candida overgrowth. Do you get bloated as well?
There isn’t supposed to any Candida in the small intestine as far as I understand. But I’m thinking, if there is Candida overgrowht in the colon and if the valve between colon and small intestine doesn’t work properly (as in the case of SIBO it doesnt) then what would stop Candida from expanding into the small intestine too? Then again if it did get there, would it not regulate the bacterial overgrowth there? But I guess it is possible to have both.
Funny thing about those Swedish bitters: when I googled them after not finding them here even though I live in Scandinavia (next door to Sweden really), I found out that they are actually Swiss!
I understand your frustration with the very restricted diet. I personally don’t follow this diet or that any more. i test things for myself and choose foods that I can digest well. if something gives me gas or bloating I try to eliminate it. Though I play around with this too. For example I’ve found out that I can have eggs but just not in the same meal I have certain veggies (ie cabbage). I can also have raw cauliflower salad on its own just fine, whereas if I have it as part of a bigger meal I will get gas afterwards. In the long run though I am generally just trying to improve my digestion and increase my metabolism as well as resolving the constipation issue.