I was just wondering how many a sheetcake would serve?
What size pan are you going to use? and do you plan to make it one layer or two?
It is a 11 x 15. Just a single layer
Here's a link to all four Wilton cake preparation and servings guides:
(Gives batter requirements by pan size, as well as recommended baking temps. and times and party or wedding servings by pan size.)
Doug has provided wedding servings help thread for sheet cakes:
Indydebi does the math for 2x2 and 2x3 servings from single layer sheet cakes: