Hi
All I can add is what I was told by my team
To start with after 4 weeks of Purée food and then 4 weeks of mashed food all in a dish no bigger than a ramekin, then onto solids but still in a Ramekin, then slowly over the next six months build it up to no more than a tea plate.
I am now almost a year out still eating no more than a tea plate so nothing is getting too stretched, I still don't ever feel hungry and my pouch is still able to tell me when its full.
In the first stages the food is too fluid to stay in the pouch too long so you could probably eat more than recommended but only in the Purée stage, once the food gets thicker it will or should stay in the pouch long enough to tell you when its full, and that will probably be pain, so learn to stop as soon as it tells you to stop, because just one more spoonful could be very painful or you could bring the lot up, and vomiting with a bypass is a very odd thing.
Hope this has been of help
Paul