Thanks coastrat. I got to be too simple for that stuff. I don't know how I can measure 22 degree "sail's incidence" for example. It must be very A-cat specific.
So some practical details...
I went out today to experiment and get some details on what I am doing.
Wind about 10kt, down to 6 or 7, up to just below 15. That much I can handle solo upwind with jib. Downwind: boards up, barber hauler 4" up from the front beam, main traveler 14" of the center, sheet tight, both main and jib cleated, handling gusts with rudders only, sitting in the middle of the tramp. Max hull flying time was under 5 seconds. Afterward talked to A-cat sailor and he said it takes about 12kt to do it on his pretty new boat, so seems I was underpowered. Talked to Jim Young
http://jimyoungsailing.com/ and he pointed that square top is essential for that, because more power aloft creates that nice heeling force.
On Nacra F18 we would do wild thing in this wind, but solo on 5.5 just doesn't work... unless I am missing something. I guess next time I'll be sitting on leeward hull...