Going to burn all my current dvds, for backup.

Hi all.

I have around 50 dvd's I would like to burn to dvd-r for backup purposes, incase scratches or anything of the sort occurs.

Currently, I just use dvd shrink to rip and shrink then use nero to burn to disc. Very straightforward and easy.. But most of the time the quality is only 50-70%
I usually keep the 2 channel audio and 5.1 channel audio, mainly because I dont really know the difference. Other than 2 channel sounds louder on my tv than 5.1.
But sometimes the only 2 channel on the disc is commentary, so I get tricked like that alot, which is why I just get all audio English 2 and 5.1

Im wondering, if theirs a program that is better, that would make the quality better, even if only slight. The program has to be relatively easy to use, or atleast have a guide to guide me through it.

If dvd shrink is best, does deep analysis make any difference in quality?

I am only burning to 4.7 gb dvd-r
Thanks all.