Stephen
Glad it worked.
If you are just wanting to email the result I would set the ppi in the dialog box to 72 - ie the standard screen resolution.
If you are wanting to print the output I set the ppi to 200 which is more than adequate quality for contact prints. That way you end up with an A4 sized image that is 1600 x 2200 pixels. You might find that the processing time is quicker rather than generating a 6000 x 7000 px output (but there again you might not cos I haven't tried it
)