Yes - sometimes Descreen is called magazine/photo - glad you found it!
We require JPG as the filetype for all covers, so the corners will appear white if they are rounded - as you say if someone wants to round them then they can do it themselves but I doubt anyone does this!
The scan looks okay now, the spine will be fine (in terms of reflections). But now that I can see it properly you are right, it will need a lot of TLC to bring it back to looking 'original'. Give it a go and we'll see what it looks like. There are some other tips for finishing a scan here that you might be able to use:
http://www.customaniacs.org/forum/tu...d-product.html
Removing Scan Noise from Credits, Legal Text etc.
How to Straighten an Image in Photoshop
Colour Correction using Photoshop Curves
http://www.customaniacs.org/forum/tu...ver-label.html