I'd say definitely the lidded cups. I could stand and be talking to bride "A", and without breaking eye contact or stopping my conversation with "A", reach down, pick up a sample and a fork and hand it to bride "B" ... who has now been acknowledged and will munch on her cake while waiting for me to finish with "A".
And I also believe it's true about some health dept's require the lidded cup as opposed to just open food. (In my county, if I sample out cake in a cup, it's A-OK. But if I sample hot chicken from an open chafer, I have to get an off-site temp health dept permit to work the show.)
I did not take a calendar simply because I find this is NOT the place to make appts. You are here to make as much contact as possible. You have about 30 seconds with each bride, if you're lucky. Even tho' I was going to receive the registration list of brides from the show, I did collect my own list of emails with the promise to send info to them. That's when the discussion of appts 'n such are made.
I worked the booth solo, but since I love a stage and a microphone, I was in hog heaven, being busy with so many brides!
I also agree that if you can have a helper with you, it would be a big help.