I finished it tonight. Got all the formulas and equations set in Excel and made enough pages for every month for the first five years I'll be in business.
I even managed to show a loss! It's just one month, and it's just about $285. I haven't totally cleaned up the numbers yet, I haven't accounted for repayment of loans, nor have I redone the "wages" line to take into account hiring more people than myself and one 20-hour employee. This means there will probably be more months showing a loss, but this is ok. This is where I figure this stuff out, more or less, so I can include the loss in my working capital needs and borrow enough to cover it.
The next step is to clean up the numbers and then move on to another section of my business plan.