I am wanting to make a cake that looks like the box for a wine bottle and has a wine bottle in it. I was going to use shaved white chocolate for the filling around the bottle and attempt a wood grain on the box. I thought I could use my 6 in round cake pans and then cut them in half. I need to feed about 40 people and I'm having a hard time figuring out what my cake dimensions should be for that amount of servings. Any help would be greatly appreciated!!!