I would start with 800 words and scale down to 500.
That sounds like a very good idea. I would say 700 and scale down to 500, because it is hard to get rid of 300 words...
Hey, the most important thing is to provide the reader with an experience. This is what I say all the time to people. Remember your purpose. Make sure you know your purpose. The purpose is to make the reader feel surprised about the details and interestingness of your plan.
And your plan is as unique as you are, as cheesy as that sounds. It is a particular perspective on a particular industry, and it has all your personal characteristics. So... show them what you have in mind.