I have done many a show in one room apartments and smaller homes. Several shows were in the living room and people sat on the carpet. And they loved every minute of it.
I am not saying you have to invite the world. If you only want 10 people to show, you may well have to invite 40 people to reach that goal. That's all I am saying. Just because you invite only 10 doesn't mean all 10 will be able to make it. I am not saying your friends will stiff you - but if their child has a basketball game that night, they might not make your show, or if that's their night to teach religion class, they can't exactly skip out.
That's why you are encouraged to invite many people because you never know what's on other people's schedules. In all likelihood, most people will still place an order, which is good, but you have to prepare yourself for the fact that people may have other plans on the date you chose for your show.