I've updated the spreadsheet download to include both the original Excel version and an open document spreadsheet. Libre Office 5 appears to run the .ods file quite well.
Usage: X2 Scheme template tab
Each row is a single line-item in the final production. You can add more rows by copying an entire row. Column I (labelled Colour) can be edited freely. The four adjacent columns should then update the numerical values automatically. Colours will need to be manually edited.
Usage: Calculator Tab
Cells B3:B8 are the main input cells, accepting colours as RGB values. Within those rows, The headers in columns G to Q are:
R - Red as %
G - Green as %
B - Blue as %
H - Hue as 0-360 (0 red, 120 green, 240 blue)
S - Saturation as % (0% grey, 100% saturated colour)
L - Lightness as % (0% pure black, 100% pure white)
X, Y - X/Y grid coordinates if the hue is projected as an angular line on a chart from a 0,0 origin.
Warmth - My own measure. Multiplies saturation by angular distance from 30° Hue (orange).
per Bri. - The perceived brightness measure, subtly different from the L value.
Cell B12 contains the averaged RGB values of the input cells.
Cell B16 contains the averaged HSL values of the input cells.
Cells K14:M14 contain the averaged HSL values of the input cells.
Cells K15:M15 contain optional inputs that "intercept" the averaged HSL values of the input cells. These can (and should normally) be kept blank. If anything is in them, they will override the averaged values. They can be used to modify the averaged values
Usage example: Suppose i want the average colour of France and Spain, with saturation set to 50%, I would enter France and Spain's colours in the input cells (leaving the other four blank). In cell L14 (which intercepts the saturation), I would type "=L14*0.5", which will return half the original saturation value.
Scrolling Down a Bit...
Cells D35:E39 contain a simple RGB to web-friendly hex converter.
Cells G35:H39 contain a simple web-friendly hex to RGB converter.