I was doing about 1/4 cup during the puree stage as well. I never felt hungry, nor did I feel full. It was just a matter of getting in the protein I needed at that point.
I was never able to make such tiny portions of food last 30 minutes or more. I made a point of chewing everything thoroughly when I got to solid food, but I still couldn't make my meals last long enough. I'm not advocating faster eating, just sharing my experience.
I also wanted to note that my surgeon and nutritionist said that I did not need to stop drinking 30 minutes before eating, only after. That's what I have done since surgery and it doesn't seem to have been a problem. Again, just my experience.