Welcome back after 4 years.
Are you considering deep dish or thin? Despite the logistical difficulties JT noted, deep dish may be your best option because the logistics of thin, despite not needing pans, may be worse.
With deep dish, you can probably get 4 pies in the oven, so you can probably have 4 pies (or even 8 if you don't mind holding some hot for an hour) ready when your guests arrive. I think my experiments would be on a formula that holds well both unbaked and baked. Get a bunch of pans so not only could you have a lot of pizza ready when your guests arrive, you could have all the pizza you plan to bake assembled and ready for the oven.
When we do Detroit style here at the house (the only experience I have with pan pizza), Light eaters eat 25in^2; typical eaters eat about 55in^2. I'd say a minimum for planning purposes is 40in^2/person. Again, this is Detroit style. A heavy Chicago deep dish might require less per person.
For thin, 40 is a lot of people without commercial equipment. If you're baking in a home oven and can do 2 pies in 30 minutes (I bet it takes at least that long to make, bake, and slice), you're looking at needing an hour to get 1 slice to every person (and that is with two pies ready when they start to arrive). With people talking to you and what not, I think you'd be doing good to maintain a 1 slice/hour/person rate.
Give a little more specifics about exactly what sort of pie you want to make, the toppings, and your equipment, and we can probably give you better help.