Also, depending on how you want the user to get this workbook, your choices can increase or decrease. To do something similar, I reverse-engineered the HTML format that Excel uses and wrote a Perl script (plus templates) to write out that. Then, all I had to do was give the user a URL that they could give to Excel as a filename and it would open in Excel. This was a very effective delivery system, but it did take a few days to get up and running.

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We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.