I found the following example code to allow overlaying of indicators from a longer term time frame (weekly) on top of the daily chart

protected override void Execute(){
// Plot the weekly MACD in our daily chart
SetScaleWeekly();
DataSeries WeeklyMACD = MACD.Series( Close );
RestoreScale();
WeeklyMACD = Synchronize( WeeklyMACD );
ChartPane MACDPane = CreatePane( 50, true, true );
PlotSeries( MACDPane, WeeklyMACD, Color.Maroon, WealthLab.LineStyle.Histogram, 2 );
}

Question 1: What options do I have if I want to use a 3x larger time frame - i.e. if I work with daily data how can I get 3-day data plotted together with the daily data?

Question 2: Is there any means to synchronize 2 separate Graph windows (daily and 3-day) such that moving a cross-hair in 1 window will move the cross-hair in the long term (3-day_ window in sync?

1: Wealth-Lab doesn't support n-day data conflation out-of-the-box. Depending on the starting point, the entire chart would change, and so would any indicators and therefore trading signals based on the conflated data.

That said, if you want to come up with your own method that a) standardizes a starting point of an n-day conflation, and, b) that synchronizes the result, it can be done - it's a custom programming task.

Also, it would be farily easy to create an n-day Chart Style. Maybe one of you motivated programmers who finds an n-day chart useful can do that!

2: Not for the crosshairs; but since you can link charts (chain link icon, lower right of chart window) of different time frames such that they always change to the same symbol, it not a huge step to think that a crosshair in one of the windows could be synch'd to linked charts. I'll put it on the wish list.

Just thinking about how the crosshair would be implemented... why not display it in every chart in the Workspace, synchronized to the bar in the chart where it's being positioned?

Currently, you can position the crosshair in different charts, leaving it at different locations. So, there would have to be a button to "Enable Crosshair Synch". Just thinking out loud.