same mph on 50 shot as 75?
11.7 with 1.62 on 75 shot
11.9 with 1.77 on 50 shot (needed a better launch obviously but 11.7 seems attainable)
both mphs are on point 114.8
Also...be sure bottle psi is EXACTLY the same for all runs. Especially if your trying to accurately measure the difference of an additional 25 hp of N20 during a run.

