Surely I'm not a superstar programmer by Joel's standards. Nonetheless I have written quite some successful projects in my 20 years career as a developer. I could have solved your questions. But less from my experience at work, where in fact a lot of the more complicated work is done by asking your database or a library function to do it.
But if you decide to hire less experienced people, you should consider using technologies that are easy to handle. For example if you planned to use C++ for the whole project, then limit the C++ part to libraries written by your best people and let the others implement the user interface in Visual Basic.