Hi,
Your description explains all the requirements pretty well. (You wouldn't think how scarce these descriptions are)
I have one questions only. Since your source files won't contains these macros and I guess you will have to manually copy-paste the content of sheet 1 and 2 from other files, I can propose you an extra button that opens the file dialog, you select the source file, and the content of the selected file will be pasted into the macro file. Maybe it doesn't save a lot of time but if you like it, I can do it (included in the proposed price)
Regards,
Balint Kolosi