Yah I realize that, so I'm trying hard not to get a glimpse before hand. As long as you're honest with yourself enough not to peek, it should be ok.
The problem with just "scrolling a chart" forward....the rest of the program is not staying in synch with your chart (Time and Sales windows, other charts, quotepages, data of other symbols, etc). In addition, any signals and alerts that your chart may be setup to trigger won't fire. Investor/RT has a global playback feature that will playback any period of time on any group of symbols. This video highlights the feature: http://www.linnsoft.com/videos/playback/