Regarding the tightness around your midsection, I had it after my whipple as well. I think it has something to do with how your abdominal muscles are sewn back together. I am four months out and aside from sensitivity on the surface of my stomach, the tightness underneath at the muscular level is almost gone. I suppose everyone is different with respect to healing duration, but I think the thing you're supposed to worry most about a hernia.
Regarding the Creon intake, the dietician said it would be trial and error. Your stools are supposed to be the best indicator. If they are floating and greasy, you either did not take the creon soon at the right time, took too little, or you ate food that was too unhealthy (too greasy). A more general indicator is continued weight loss. Not having enough of the enzymes can lead to malabsorption... your body simply doesn't suck in the calories from the food you eat very well.
Hope this helps.