Dual Layer Burning Help

I am using a Sony DRU-710A and would like to burn DL movies. I tried using the Memorex DL media with no luck. After reading posts in this forum, I decided to try the Verbatim DVD+R DL media.

I am using:
DVD Decrypter or DVDFab Decrypter for ripping
DVD Shrink for shrinking and burning
Also use Nero 6

For single sided disks, I have been shrinking/burning in file mode. Are there advantage or disadvantages to burining DL disks in this mode? Do I need to figure out how to use ISO files for DL burning? If so, are there any suggestions or guides to help me get familiar with that?

Any help would be appreciated. Thanks-

Verbatim, actually, is the best solution for DL backup.
Your softwares are Ok, I suggest you to use Anydvd or DvdIdle Pro too, because Dvddecrypter is old and has trouble with the latest protections; for DL you can use Dvdderypter + Anydvd for ripping in Iso mode and then burning the MDS file generated with Dvddecrypter or Imgburn ( in ISO mode ), because the MDS file containes information for the layer break. For single sided DVD there is no difference in file mode or Iso mode