A DVD-/+R or DVD-/+RW is not RAM (Random Access Memory)
As far as I know you can't use a DVD instead of a Harddrive.
A clone is an exact copy of your Harddrive including the partitions etc, therefore it can only be put onto another Harddrive.
You can store a backup Image of your Harddrive on DVD (make take more than one dvd - depends on size of image)
What setup do you wish to 'end up with'?
please give us some more details.