Recommended speakers for Shindo Cortese

This is simply my guess. I am sure Don Better, Matt Rotunda or Jonathan Halpern know much better. I would think you would want a speaker at least 90 or 91 db, w/ a fairly stable 6 or 8 ohm impedance. What is the efficiency on your Coral Beta's.

there was a pair of Auditorium 23 Solovox speakers listed recently ... should pair beautifully with the Cortese. expensive though even used as they are rare

Think vintage - like old Altecs.

My current Corals are 98db I think

OK. If your speakers are 98DB, don't do anything until you hear the Cortese/Monbrison combo w/ your Coral's. In the meantime, you could figure out an alternative if you don't happen to like it. I wouldn't go crazy over it until you hear it w/ your speakers though. Of course, easier said than done because we are all kind of crazy already.