I was on a 69" Triumph and moved to a 67" Radar Vice after also trying the Senate, Concept, F1X, and V. I was not getting another HO. At first I thought the Senate was the ski for me and it was hard deciding between the two Radars. The Vice just had more aggression, though the Senate had better deep water starts (IIRC it was also a 69 vs the 67 Vice). I'm about your size and start the course 15off going 32mph. I think the Senate would be a great ski to get you into higher speeds
EDIT: Also just because manufacturers recommend a certain speed for their ranking of skis doesn't necessarily mean that the ski won't perform at slower speeds. Make sure you spend time on the ski before purchasing!