Regretfully, you can't tell when the stoma will be at it's most active as we are all different.
For me, transition from eating to output is around three hours - for my partner it is around a day…
I have a colostomy .. trouble is I like my food
That makes it a little more difficult to "guess" when your stoma will be more active as you have a long food transition.
We all "burp" - mine did a cracker in the office yesterday, but it's just one of those things where there is no easy answer. Sorry!