We did the same - just asked the server to bring us whatever she recommended. (We knew we wanted the 'olives'.) We told her what we wanted to spend, and she took charge. It was a really fun evening and the food was wonderful.
We did the same. In addition to the olives, I knew we wanted the mini-airbags. Gave her our budget for two with a bottle of cava of 150 Euros and we came in just under that. That seems to be about the rate for two if you don't go crazy.