if you consider to use the last code, need to start your application with the latest sheet, otherwise you get trouble assigning names
while the first option gives you always the initial speadsheet and will write files in numeric order.
There are other options, of course (aren't there always).
For instance, you could check for which names already exist on disk, and generate the next one in the series. That way, you'll always add onto the end, with little danger of overwriting.
