during flares,my doc recommend taking 1 cap after dinner and no vsl during remission

The research studies on VSL 3 for active UC are using mega doses of 4 sackets per day (double strength), which is equivalent to about 8 sackets of the regular dose. I think this is 16 pills per day.

If you want to see if it works, I would recommend the dose used in all the research studies, but start very, very slowly.

1 or 2 pills per day is likely not going to help because 16 pills is the therapeutic dose used in placebo controlled studies for active colitis.

Expense is a huge issue if you are using the recommended dose during a flare, so maybe try it for only 1 month.

I recommend buying it from the manufacturer directly because they ship it with ice packs: https://vsl3.com/

2 day fed ex is only 7.00. You will get a large box with ice packs.

As it's a probiotic there's technically no "dosage", however, like everyone else, I would recommend starting small and building up just to see how you tolerate it. Given that probiotics only transiently pass through the gut, and only do so while you are taking it, I think the more the better when flaring, and that's what I do. When I'm in remission, I just take one sachet of a morning as a maintenance, unless I feel very under control and I don't bother as a cost-saving measure. I think cost is a rate-limiting step with regards to dosage for most people, myself included.