Extra tours at Kennedy - worth it?

[GEM]

Hi! We are planning to visit KSC for one day on our trip this December. I did some research and found out they have two extra tours that cost an additional $20 each over the regular price of admission. Has anybody done these? Are they worth the extra money? Would we even have time to do one if we only have one day to see everything else? If you think they are worth it and that we would have time, which one would you reccomend? Thanks!!