Ok, as promised, here's the report from the first concert with the ACB picc.
Read about "Acoustics" - description of the very unconventional hall we played in. Lots of open spaces, lots of glass, two staircases... during rehearsal, sound just vanished. At the performance, the ACB without amp easily filled the hall without effort, blended well with all the brass section of the orchestra (one Lechner Bb, one Cerveny tenor horn, one K&H trombone and a really ancient Lidl tuba). No problem with intonation even after a long wait for it being played - only used in the final piece.
Audience were thrilled, gave us 14 minutes of applause. I'm content.