Im guessing 12 knots. The videos are sailing across melville water. My home water..
The waves in that area rarely get much bigger than twice that size. The wind however is generally twice the strength what you see. So the moth sailors are used to sailing in 25 knot and greater wind strengths. Here at least they dont have huge seas to content with . Other localities in the state do.

I would suggest all current foiled moths are based on standard moth hulls. The videos look like Growler hulls but I may be mistaken. These boats have a foiled plate and rudder fitted. Although many Aussie moth skippers may rip out a hull during the winter.

Mary, the choices of wings is almost personal. The reason for the fabric panel makes it easier to slide out and more comfortable in non hiking conditions. I havent seen a solid wing in years (too heavy many hulls are between 7 and 10 Kgs)
Hope this helps
Stewart