Hi Fattouma, you'll find bypass patients can eat larger amounts than us sleevers. I was the same as you with my sleeve initially where 1/2 tin of soup just wouldn't have fitted in, now 8 weeks post op I can manage about 1/3 can.
Debbie, you'll know when you've had too much, you'll feel really uncomfortable, not just heavy. Your not even 2 weeks post op so there is still swelling and healing going on in your tummy which will take another few weeks to calm down. 25mins for 300ml of soup is good and I hope that means that you are enjoying it too, eating slowly is the new way to eat for you now.