Finally I gave myself a Christmas present--a freeride foil. I used that on a small slalom board.
After two seesions, I managed to get some continuous flight, occasionally touching down. But I found my stance was awful. I had difficulty in using the harness. I found the boom was too low once in the foot straps and flying. Hand height at waist holding the boom

I constantly bend my front arm to control the power and held the boom close to the mast. I had to very actively adjust foot pressure and sail to control ride height and windward/leeward trim of the board. Is it just take more time to get used to it?
Setup: boom at shouldet height (as normal windsurfing), seat harness (hook at hip height), 22 inches lines, mast track 133 from tail, freerace camber sail up to 6.5m
My thought: raise the boom, try a waist harness (but then the boom will feel even lower?) Or everything will be sorted out after more practice.
It seems that I dont need much power for foiling, not much power to sit into. I mostly fly without hooking in for easier trim adjustment, and less violent crash