Mine is 3/4" tapered, but I don't think it's factory as it's a Uflex rotary unit. I do however think that it is the same size as the factory ones. When I put on my Sport pilot I had to use the 3/4" to 1" adaptor. The mac wheel, which is stock, when right onto the sport pilots 3/4" tapered shaft.
Not quite as grand as the lewmar one, but here is the folding cockpit table I have in my mac. It's about as big as you can go and still get around it to go inside.
I'm actually thinking about a major rebuild of the steering on my MacX anyway (including custom pedestal that provides more foot room and more instrument room). The boat really needs a larger wheel and a slower steering system. The factory steering is around 3 turns lock to lock. I think 4, or even 5 would be good for the sailor in me. The wheel on the X is better suited for a small sports car, not a sailboat (size wise anyway). The big wheel would be icing on the cake
SK
I saw the wheel on one of the boats at Oakland's boat show last month. The black grips are heavy-threaded plastic collars that secure the spoke, or permit it to part, for folding. It was a very impressive wheel, and a very slick design. But, I'd have to guess that wheel is >$500, and I cannot imagine it would fit on a Mac.