The first thing to do is get a decryption/ripping program that will work with newer, more advanced copy protections. The main choices are AnyDVD and DVDFab. Those are both commercial programs, but have free trials.
DVDFab has a section that is free to use, and will remain operational even after the trial. It is called DVDFab HD Decrypter, and will do the process of decryption and ripping to the hard drive. It won’t compress if that is necessary, but there are free options for that, like DVDShrink.
www.mrbass.org (for DVDShrink)
The next step is to check your Optiarc drive. Make sure you are using an 80 wire IDE cable with this drive. Make sure dma is enabled. This guide will show you how to check that: http://club.cdfreaks.com/f61/troubleshooting-enabling-checking-dma-windows-vista-xp-2000-me-9x-101616/
Now on to your choices in media. The Sony single layer disks are ok. The Memorex are not. If you are going to burn to dual layer, use Verbatim, as they are the only ones reliable enough to be recommended. And if you are going to burn to dual layer media, I strongly urge you to look into using a burning program called ImgBurn. It is free to use, and is one of the best for setting the layer break correctly on dual layer burns. It is my main burning program for all types of burns these days. You might also be interested in looking through the guides to using it: http://forum.imgburn.com/index.php?showforum=4
Now, burning speed. If you are burning 16x single layer at 2x, there is a good chance of producing poor burns. Read this stickied post from the Blank Media forum: http://club.cdfreaks.com/f33/slow-write-speeds-modern-drives-modern-media-no-good-247643/ My advice is to burn these Sony disks at 8x in your Optiarc. 12x might also work well.
Use the Memorex DL disks to decorate your Christmas tree. Buy some Verbatim dual layer and burn them at 4x.