We took a trip with DH, me, DD12, DS9, my sister, BIL, DN(iece) 9, DN 3, DN 2, and my mom and dad last summer. So, total of 11 people. We stayed at Disney 8 days and seven nights. Our food totals were:
We spent $122.37 out of pocket, mostly on alcoholic drinks and appetizers.
We spent $456.10 on tips.
We spent $2190 on the dining plan. To see if we got a good deal, we kept receipts and discovered that if we hadn't been on the dining plan, we would have spent $3261.89 (not including the tips or things we bought out of pocket).
We ate at a lot of character meals because it was probably the only chance our nieces would have to do so - their parents are not at ALL interested in paying Disney prices for food and lodging, so we treated them so we could do it our way, lol. We didn't do any signature meals.
On our next trip, we'll probably spend $250 on food. We have the free quick service dining, so we've only booked two ADRs, and there are only four of us this time.