Coming a bit late to this, but thought I'd respond to your questions.
1) what was the extent of your UC. - Proctosigmoiditis, mild to moderate, inflammation mainly in rectum spread slightly into sigmoid colon.
2) what was your dosage - 500mg, 1xday. (Plus 3.2g oral 5ASAs)
3) how long before you started seeing initial positive results? ( passing of gas, reduced BMs, lesser urgency, etc) - I actually had immediate improvement (literally overnight). Blood, mucus, and diarrhoea all cleared up, and was having normal BMs within 36 hours. I have since had a minor flare up when my GI told me to stop taking the supps, but symptoms were gone within 48 hours of starting taking them again.
Since, I have had, thanks to antibiotics, another mild flare up. Symptoms were helped by a course of prednisolone foam enema, and I had a flex sig last week. My GI told me from this that my rectum was free of inflammation, and there was only a patch that had spread a bit further into my sigmoid, which I've been prescribed 5ASA foam enema to hopefully deal with.
I do think that the supps are hugely effective if the inflammation is limited to the rectum, as they do appear over the last year to have completely dealt with it for me, but if it's spread further into the sigmoid it needs an enema to deal with it.
So, after that long ramble I'd definitely recommend sticking with the supps!