Architectural Plan Takeoff formula for stock length counts

Hello,
I am a new member to this forum and would like to thank anyone in advance if you are able to assist.

Problem: I need a spreadsheet to calculate the total amount of stock lengths I will need for a group, or an assembly, of products. Each detail# will consist of anywhere between 2 and 6 different part numbers all in stock length form.
Example Data:

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Architectural plans have 10 openings that are 145"w x 120"h.

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The top of the opening is detail #1

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The 2 sides of each opening is detail #2 (#2 shares some of the same part numbers as #1)

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The bottom of the opening is detail #3

I imagine the spreadsheet would have these columns for data entry:
Detail # Length Count Qty.

The results would be be in a table that would list all of the relevant part numbers I need to order, based on 24' stock lengths. Any suggestions are appreciated.

Thank you for the guidance!