The one up scene looks (from here) to be mostly a local club scene. That's a good question for the EU guys... What is the level of participation for one up spin sailors in the EU. I wonder how much of a market there is for a single handed spin cat racing program.
For every club sailor, how many of those travel to events other than their own puddle, without a proper survey I guess I could use the F16 park at Datchet with 11 boats, only 1 has travelled to an outside event this year and i would guess that is about the norm.
In my view this is exactly where the manufacturers get it wrong, which market should they sell to, the clubman who often doesn't race or the clubman who races regulalry. At 11 : 1 it is a marketing no brainer but unless they can get the publicity from winning races then the clubman won't buy the product as they need to aspire to own the latest all singing and dancing toy.
As to EU preference to one or two crew, probably a very high number are sailed solo with an occasional crew for comps, sort of the other way around to the States.