For the record in this conversation: I reviewed alternatives for a Booking system (which sadly never happened) & concluded that GitHub - PloneGov-IT/rg.prenotazioni: Prenotazioni product for Unione Reno Galliera would be the best for my situation. It's Archetypes based, but an upgrade to Dexterity was under consideration at some point.
I guess @keul you might be aware of that anyway?
(prenotazioni =Italian=> reservation / booking)