Since you have the 2500, you might as well try the Mad Dog 2.F9 release. It supports bitsetting on DVD+R and DVD+R DL.
The DVD+RW bitsetting is another animal. It will probably only work with never-been-used DVD+RW media. Not sure if the 35x0 workaround works with the 25x0 though. Check the BIG NEC FAQ for the workaround.