I have been paddling into big waves at Mavericks on a SUP. I am not sure how you would ever do it prone.
1) I am using a Big SUP (by foil standards) 7' 4" board because you need the board speed
2) High aspect wings. GoFoil GL210 and GL140. Once you get up you need speed to stay with larger waves anywhere from 20 to 24 mph or up to 40 kmh.
3) I have been taking off on the seam between the whitewater and shoulder that is steep enough to just drop and run. Sometimes you get lucky with a chip-shot whitecap takeoff But with big waves you then have to be fast enough to crawl over and back into the trough.
4) I can't convince anyone to come out with me. The only exception is Haley Fiske who has the skill and is far crazier than I am.
I would say the bowl at Mavericks No-Way (but some kid may prove me wrong). The shoulder at Mavericks is softer but moves really, really fast. I can catch 20-30+ footers there but I have been on a 12' SUP gun with a good amount of speed.
These were 12 to 15 foot faces. On the GL210.