If you actually tried the Oversampler Sound Driver Demo and the sound skipped on you, it's because DOC registers $A0, $A8, and $B0 should have been initialized to $02 (one shot) instead of $00 (free run). It cost me about 6 hours to track that down. You can patch it yourself or await the next release of stuff here.
Excellent progress with GTE too. I should have something else to share soon.
-Chris