Ok, I successfully updated my 851s to an 832s. My Verbatim pack of +RW, +R and 1 DL +R are coming in a few days.
I have an old Sony DVD player that only reads -R media and -RW. If I wanted it to read +R media, I would use the booktype utility from Liteon and set it to DVD rom. Does this mean that my DVD player will only read DL +R media if it is set to DVD rom?