There are several factors to how many cupcakes they will need for 110 guests. Assuming that the cupcakes will be the only dessert option there, the biggest factor I find is how many different flavors of cupcakes there will be. 3 or less flavors, I generally recommend 1 - 1.25/guest. If you have more than 3 flavors, I find that people will take more than 1 cupcake because they can't decide which flavor they'd like and want to try a couple different flavors. Another big factor is how many children will be there. Kids will typically take more than 1 cupcake if given the opportunity
I specialize in cupcake weddings (I don't offer tiered cakes). I bake on Thursday, frost and decorate on Friday, then deliver on Saturday. I usually do 3-4 weddings per weekend during the summer and right now I'm doing everything myself (I don't have any employees).