Tension vs Pitch Chart
This spreadsheet is best viewed in Full Screen mode. Note that you can move the chart area around to suit you, using the "hand tool" that appears when you move your cursor over the chart.
You can also download it for faster and more reliable operation (the TIP about moving your cursor over the data is available only if you download and run the spreadsheet).
I use this tool for selecting all string gauges for various tension setups, and for baritone string selection. You can use it for your own dulcimer, by putting in your Scale Length in the red data box.
Here is a more versatile spreadsheet for choosing string sets.