Made a happy discovery today. If I leave the jumpers in place for L1 WB operation on the POD I only need to change the setting in the bios for L1 to WT I order to play Duke3D. The sound test is still trashed but actual sound during gameplay seems fine. Overall hit to system performance is almost negligible, Duke3D runs a whole frame better, and I can always switch the setting back with a simple reboot, no fiddling with jumpers, yay!
BTW this board gets the highest Duke3D fps of 42 at 320x400, beating any other socket 3 hardware combo I’ve come across yet if memory serves correctly. Will def go back and double check though.