So the gig is over. It was a high quality performance. The musicians were good pros, so I didn't have to bother with mic technique or stuff like that.
The cajon was made by someone in Jerusalem and seemed to be well built. The player had a high hat and two other cymbals, one thin crash and the other ride crash. I miced the cajon with a 451E on the front to capture the snare sound and a plain 58 at the back, not looking into the hole. It sounded crisp and fat.
Good and interesting music, good players, not a single glitch in the sound- I cannot ask for more.
The pic was taken during sound check/last rehearsal, when phone calls were still alllowed
Thanks to all for the good advice.