After making new 24bit/192KHz room measurements with MathAudio RoomEQ, the MS-3 and dspMusikLCD 2x16, have The Megaliths sounding great with all the music playback tonight. Classical, Jazz, Pop and Rock all sound wonderful and very open like music in a space.
First test was the original CD version of Pink Floyd's Dark Side of the Moon. Sounds better than I remember it, and now need to get the DSD version online for a comparison.
Almost time for friends to come over for another listening session to gauge progress.