Hi Paul,
After a careful further review, looking very closely at each of these two library's detailed list of instruments and articulations, there are no exact overlaps. Some of the differences between Synchron Percussion I and II are quite subtle, however, such as the very precisely identified instruments and articulations for Timpani and Bass Drum. Thanks for providing your clarifications.
After I purchase and preview all of the instruments and articulations in Synchron Percussion II, I'll have to get back to you as to whether or not my ears are still capable of distinguishing the subtle differences I saw between these two related library variants, especially given that I've listened to a whole lot of Return to Forever (Lenny White, Romantic Warrior era) Led Zeppelin (John Bonham), and Mahavishnu Orchestra (Billy Cobham) during the past many years. It also likely does not help that I listen to Rachmaninov's piano concertos only with the volume set at "11" (ร la This is Spinal Tap) ๐ ...
thanks again and best regards,
jim