If you develop a good Profit & Loss Statement for your existing business for the current year or for the first year of your proposed business, you can use this data to actually project how much sales you would need to yield the income you want and the profit margin you want. You can plan ahead as far as you want. Sound impossible? It's actually pretty simple and can be pretty accurate plan.
Then the question is; is your market going to be big enough to provide you with 12꽭 leads for the next year and how many will you need each of the following years? It may be easier than you think to figure this out. You would do some research and with the aid of the U.S. Census Bureau you can roughly determine whether your plan can be supported by your market or not. So what do you think? Is it better to build a business plan around what you want in life then see how your business can maybe give you that or is it better to use a sample business plan for a small business where you are probably guessing?