I think in situations like this where you know the staff, chef, etc, you are afforded the opportunity to be fliexible w/tipping... and you should be. For example, next time, send a few drinks back to the cook staff (or chef).

At a restaurant near to me, I come to know the chef and he surprises me w/dishes every now and again. Most often, I: 1.) tip the barmaid a bit extra and 2.) either send a drink back or have the barmaid deliver a tip for me to him.