Have grown up with a wide variety of cats I found that 1 cup of dry food per cat daily (I would put it out fresh in the evening, just before the family ate- less begging @ the table) was plenty of food. one quarter to one half can of wet food for breakfast seemed to perk them up for a day of happy playing while we were out of the house.

As for indoor/outdoor- we had outdoor cats for a long time, as they aged we kept them in @ night, then they just stopped asking. I had one cat that was totally indoor, but he escaped on night- to go looking for our other kitty who had moved to a new home that day, we looked for a long time, but as we lived between two very busy streets and he had no outside experience (other than trips to grandma's on a leash), I thought that he was gone for good. After 3 days I was woken up by my roommate screaming "Buddy's home". He had survived, and found his way back, a trip to the vet showed that he was dehydrated and they gave him IV fluids, but otherwise he was fine(he was so happy to be in my arms that he didn't even flinch when the iv went in!). I lost him to old age @ 16 3/4 years- Nov '06. I am only now considering replacing him- I love the emotional support from a pet, but my Buddy was unique and I know I will never have that same connection again.