Double/Dual Layer
The largest factors in using double/dual layer DVDs are: burner, media type and burning speed. I have a Memorex 16x DDL burner and just couldn't ever seem to get good results. I used Memorex, TDK and Verbatim discs. I finally decided to do some tests and used CDSpeed to make a data disc with the different media and my burner to see how they came out. It seemed that the Memorex media ws worthless, TDK label was actually Ritek and seemed to do OK if I burned at 2x. I went out and bought a Plextor PX760A and did it again. With the Plextor and a Verbatim 6x double layer, the first layer was almost flawless at 4x and very good readings with the second layer. The Plextor was much better with the first layer on the TDK/Ritek 2.4x and a little worse than the Memorex 16x DDL on the second layer but still well under the limits (100 PIE errors max). This is a long answer to a quick question, you need to "waste" a couple of discs and test to see what media and speed works with your burner. Might find one, may not. If not, get a new burner, find what works with it and you will quit making coasters and end up saving money in the long run. The Plextor PX760A is very, very good, sells for $100 or so at Frys.com and they have had a $30 rebate on them.
Also, if you use CloneCD and use the Copy CD option, it will leave the layer break in the original spot. CloneDVD may move the layer break, but you probably will not notice it anyway since most people generally don't notice the "pause" on the original.