Correct. Do NOT use DVDShrink, for a straight backup copy onto Dual Layer blanks.
Safest method -->
Use DVDDecrypter (last version) in ISO mode (go the MODE menu, and choose "ISO READ R") to read the disc onto your hard drive.
Then, use DVDDecrypter (again) in ISO mode to do a burn back to the blank dual layer disc. Go back to that MODE menu, select "ISO WRITE W." Then, navigate to the folder where the rip is, and select the file with an "MDS" extension.
The consensus still seems to be that the best dual layer blank discs are the Verbatims, followed closely by the Riteks. I have read of lots of problems with all of the others. I have burned successfully 21 Verbatims, and 8 of the Riteks. All have been "quick tested" in six DVD players. All have been played through from beginning to end in at least one of those six players. I have yet to experience any anomalies, in any of them.
By all means, try to use the remaining Fuji (unless you can return them). But, the next time you buy, look for the Verbatoms if it is dual layer you are shopping for.