To use Heikin Ashi is a great idea as they are still underrated and underused. I have my doubts whether it is really necessary to modify them and go through the hassle of manipulating spread sheets. As a day trader you really don't have the time to do this for every stock you are trading. And just imagine you are trading 10 different stocks off of 5-minute charts. A better solution is offered by Tim Haddock, Day trading with Heikin Ashi charts. You can use this chart type as it comes with your trading platform and no modifications needed. For me this has seriously improved my profitability.