Pics of the Vista Cruise? Which part number did you get?
Model #MCUVOO. Photo attached. Use the thicker of the two rubber ring fillers with the OEM Enfield grips. I loosened up the front brake lever assembly and slid it over enough to fit the Vista Cruise bar clamp right up against the throttle housing, then slid the brake clamp back hard against the cruise clamp.
I did a 650-mile two-day trip, riding from my home in central lower Michigan up to Sault Ste. Marie yesterday and back today, and I can attest to the Vista Cruise being a grip-saver, along with freeing me from the "tinglies."
Now, if I can get the problems worked out of the bike's seating....