Alrighty, I've got everything working, but it wasn't simple.
Firstly, no matter what combination of master/slave, alone/together, or cable position the option to activate DMA never appeared for the Norcent/Liteon drive (LTR40125S, I figure based on the Liteon website). As a matter of fact, in all this drive-juggling the DMA option disappeared for my Samsung DVD drive.
Well, I might be new to CDRW, but Windows I can generally deal with. A not-quite-as-recent-as-I-would-have-liked registry backup restored the DMA option to my Samsung drive. From there, I poked around with REGEDIT to find the DMA setting on the Samsung drive. Once I found what I thought was it, I recreated an identical entry under the CDRW key. I rebooted to get the changes to "take" and *TA DA*, the CDRW drive now has a checked DMA box in Device Manager.
For those that might be interested, the entry was as follows (this is Win98):
My Computer\HKEY_LOCAL_MACHINE\Enum\SCSI\NORCENT_RWJ-401S_______Z\MF&CHILD0001&PCI&VEN_1022&DEV_7409 etc, etc, etc (really long key)
DMACurrentlyUsed 01 (Binary Value)
That should likely enable DMA on any drive(?).
I shouldn't have had to do that but I'm glad it worked. I've burned two audio CDs so far at full speed (40x) with no problems at all on some generic media. The Smart Burn feature activates quite a bit during the process, but the disks themselves are fine. It really seems like my HD (Seagate Barracuda IV) can't keep up, but I'm thinking a defrag will help.
Oh, and I was thinking of flashing this drive with the latest Liteon BIOS but I'm guessing I won't. The Nero software that came with the drive says it will only work with the supplied drive. If I flash it then the drive identity will change, correct? And then the software won't work?
Jack