I think I would expect to run the same prop as the regular 120AX, with a bit better throttle response and top end. I'd personally stick with a 16x8 or 15x10. I ran the regular 120AX on a 16x8 in the Venus and really liked it, then I propped down to a 16x6 and ran it in my Yak. The increased RPM with the 16x6 gave it more of a "4-stroke feel" with the quick throttle response, and top end was still pretty good with the increased revs. My expectation of the 120AX special would be a similar gain but without propping down.

The 16x8 was nice - it had good pull, seemed to be a good blend of power and low noise, but the throttle response felt a touch mushy; it needed some time to make RPM prior to a pull. I liked the YS due to the immediate throttle response. The OS felt more like that with the 16x6.

15x10 was a little too slow to rev up. I liked the performance some of the time, but too often it didn't have the pull I wanted. I think the special might handle it nicely.