The mast is hopefully still vertical. If it's blowing 20, you're probably not buoy racing with 8 on a SC-70, and you're certainly not doing it on a 1.5 NM course. If you want to keep playing the "what if" game, that's fine with me. If you need a second person to jibe the main, then you won't be one of the 8 people I'd buoy race a sled with. The same 2-3 guys at/near the bow will be the ones flaking the genoa, raising it, jumping halyards. Anyone with a free hand is helping to pull the kite down, and the guy driving can be a big help too. No auto helm. You only need 2 headsail trimmers, and one of them is grinding. If you''re going upwind with a #1 up, you have 3-4 people that are just movable ballast & highly capable of turning cranks.
I know you feel it can't be done, and that's your right to have a differing opinion. Mine is that it can...and has been done, and it's not as difficult as you're making it out to be. I never said it can be done in 20 kts, and I certainly never said it should be done. All I said is that it can be done more easily than you think with a crew that knows one another and knows the boat.