If yours is mounted like mine, 9 on the gauge is 2" prop to pad. Each number is 1/4 inch.
I run a 25 fury 3 on mine... Worked by Ronnie Gilbert. I run mine at 3 on the gauge and can get 72. It likes to be ran lower. The smaller size doesn't lift the rear like it should.. I'm actually getting a tempest worked by Ronnie right now (larger prop and lifts better, rides better than the sho T2). I expect it to be great... I've heard from several others that they work well on these boats. I didn't care for the sho T2 that came on mine. It rode bouncy and rough... Fell on it's face above 65 ish.