So the weather will be beautiful, it's a fireworks night, it's not a school night, the Reds just finished a 7-3 road trip and are over .500, so there is really no excuse not to have a big crowd tonight.
Last season on Friday April 18th, the Reds had returned from a road trip to play the Brewers and drew 32,629, despite a 7-10 record at the time. (Don't know what promotion was going on, if any.) They drew 26,410 and 26,902 on Saturday and Sunday.
I will guess the crowds will be around 32k, 29k and 30k for the weekend.