I would create an “Uploader” template file.
At the top of the template, set some fields to the filename and sheet name of the master product list workbook.
Have one cell as a free variable number.
You can then make a load of copies of the template
Then use INDIRECT and OFFSET (populated by the location field names at the top of the sheet) across the worksheet to return a batch of data from the master product list in 500 row chunks, using the free variable number to specify the start of the batch. Change that number in each of the uploader sheets.
Once each uploader sheet is populated, then ctrl+a, ctrl+c, Alt e v s,
and then its a clean data sheet of small file size ready for squooshing into your system. It may work without the copy & pasting, but indirect and offset take up a lot of memory.
Shouldnt take more than 5 mins to do.