Hmm…your question is actually a tough one. My first choice would be a Pioneer 112 with third-party firmware inside an external case.
What software are you planning on using to burn the DVD+R? If it’s IMGBurn, then that’s easily booktyped because the software does booktyping by default, if the burner supports it. In that case, I’d recommend a Lite-On LH-20A1P and an external enclosure. Unfortunately, the drive “un-bitsets” itself every time you restart the computer, so if you use a program other than IMGburn, you’ll have to set the booktyping within the program or download a bitsetting utility for Lite-On drives. You could also get the DX-20A3H, although there is less knowledge on this board about that external drive or the newer internal LH-20A3H model that it’s based off of.