You definitely have to narrow down what category the merchants will be in. For us, we're having a rehearsal lunch at a restaurant so we'll be using the Chase Sapphire Preferred for 2x in Dining.

Like a previous poster said, if you are going to spend a lot at a hotel (venue), then again, Sapphire Preferred is your staple at 2x points for Travel.

Other than that, I didn't come across many other categories of merchants that would receive a bonus on any other cards so I just used whatever card I wanted to earn on.