It seems that what you want to do is to back up your disks to images on your hard disk, so when your disk goes bad, you can write the image back again. You can indeed use Synchro Express and X-Copy Pro and other programs to copy from disk to disk but what happens when you run out of disks...? Try finding some new DS DD disks these days... and the old ones are just as unreliable as the disks you're trying to back up. Plus a lot of disks still won't copy.
You can use ADF tools to back up non-copy protected disks, but that leaves 95% of all games that you can't image. ADF files do not contain enough information for copy protected disks.
For some better news, though, I suggest you take a look at
http://www.softpres.org/ as what you want to do is exactly what these guys
are doing. However, you can't yet use their images yourself. I'm not sure exactly how useful it'll be to you therefore... but it does mean the data on your precious disks
is safely stored
somewhere.
