On Step #3, make sure to take a look at your actual electric bill and check what your kilowatt rate is. It can vary wildly depending on where you are and make a huge difference in your own profitability.

I'd also suggest working in equipment depreciation. Generally systems running under high load are prone to needing regular tune-ups. I can't recall how many fans and other items I've had to replace.

Finally, I'd consider re-running any set of final numbers through an Eth price of $100 and $200, just to get an idea of how much profitability will drop on market pull-backs. I'd assume needing to weather one at some point.

Thanks Jerry.