I meant to publish this a few days ago when I was in the midst of working on my paperbacks. I tested the Bookow CreateSpace cover template generator and I really like it.
The templates are similar to the CreateSpace templates, but they’re an exact fit for CreateSpace book covers. CreateSpace itself doesn’t generate templates that are an exact fit, so I have a spreadsheet that does it for me. CreateSpace’s own templates are done in batches of 10 pages, so they’re close, but not exact.
My spreadsheet came up with 3268.5 x 2475 as the dimensions I need for my cover. Rounded, that’s 3269 x 2475 at 300 ppi.
Bookow generated a template sized 3269 x 2475 for my book.
Spot on. :D
That was for the PNG file. The PDF file when opened in GIMP came up short after setting it to 300 ppi. However, that might be a quirk I just don’t know how to deal with, and I never use the PDF anyway, only the PNG, even from the CreateSpace generated templates. So there you go.
The Bookow page also has a few other resources on that page that are useful, including the ISBN-13 hyphenator, which I had fun with.