I trade 8 instruments and one of the biggest issues I have is that just by looking at the chart I cannot tell what the risk on a given trade is. The way I handle this is to calculate it by hand or in a spreadsheet, but this proves to be too slow and I end missing out on way too many trades because the opportunity is gone while I am still calculating my position size. I use Ninjatrader and am aware of the ruler, but this does not offer any advantage over a spreadsheet or calculator.