Played around with camera angles to try and best show a downwind run - used a 40cm extension on the end of the boom.
What's frothy about windfoil downwinding is you don't need groundswell and waves - wind over 15-18 knots generates windswell of about a metre, heaps of energy to carve with a foil.
Broad-reach full-speed across the swell walls then rail carve down the faces - flying downhill 2m swells for 50m, smaller swells for maybe 20m, then carve back up the faces and repeat the cycle.
Deeper downwind in stronger winds, broad reaching in lighter winds to maintain power and speed.
Mind-blowing fun

Phantasm PTM 835 high-aspect custom wing, 103W carbon mast, Simmer Tricera 5m
SW 18 knots, 1-1.5m swells