I use gelatine packs from the supermarket as I don't have mix-a-mousse at the moment, but it's the same thing!
I make it every 2 or 3 days, I use it as an extra when you feel like "eating/chewing" something.
Sometimes I can eat all the jelly in one day, sometimes it last's 2 days and then I make a new bowl to have ready for whenever I feel the urge! It does the business!
I think we are allowed 1 teaspoon of berry or orange flavouring per day, no more than that as it could knock you out of ketosis!
Enjoy, let me know what you think of it!