Spreadsheet for Gas strut force, stroke and mounting

Designing a set of stairs that raise with the assistance of gas struts (gas nitrogen spring). I need a spreadsheet that will calculate the mounting positions/angles of the struts and the force required, for varying lengths and weight (center of gravity) for a range of custom stairs. See PDF attachment from a company that did the calculations for one set of stairs, but their product is too expensive.

In summary, I need a spreadsheet to calculate the stroke and force of gas struts, and the mounting position for the struts. I have a prototype to test the results of the spreadsheet.