I use the values from the daily chart which should be 24h high/low and the settlement price should be the close. So for YM On tradestation I use the data from the previous day on a daily @YM chart to plot on my current intraday chart using my own indicator, which can be downloaded from the indicators forum. I use the 'standard' formula.
I use these calculations from experience as they have proven to be the most respected by the market on the YM, ES and
DAX.