Thank you very much, Barry. That was comprehensive.
I also ordered the Yoruba Andabo CD "Cajones Bullangueros" from Mark Sanders, who is also a member of this list, I think, although his postings are rather rare. It features cajones only and is specified somewhere as "pre-Guarapachangueo". He offered sound clips online, and I really enjoyed the transparency of that sound.
Thomas
P.S.: This is what the cover of "Del Yoruba al Son" looks like: