This is of no real help to you whatever but, I feel that CDRWs are creations of the Devil. I will not permit them to be used in my studio following disasters involving the loss of data because the damned things decided that they didn't want to retain the information on them.
They are difficult to format, difficult to use and difficult (impossible) to read when they have been written on.
I wouldn't even use a CDRW as a bird scarer and certainly not as a coaster (probably make the glass leak).
As CDRs are so cheap now, you're probably just as well using them.