I am doing the wedding and grooms cake for a wedding this weekend. It is a VERY simple cake. She wants individual cakes of different flavors. She is expecting around 100. how many servings should I plan on having. I have only done 2 wedding and have ended up with a surplus of cake. What is the general rule of thumb when planning for a wedding?

I believe you should provide what the bride and groom order. It isn't your job to choose the serving goal for how many guests... they know how many to expect based on RSVPs and I'd bet they were given more than a day or two notice on who's attending.

Absolutely. That said, I would recommend about 100 servings. Some people will pass, some will have 2 slices. It tends to work out in the end.