i have an aquacraft motely crew that i put the old traxxas system in with octura m447 and got 57.4mph. traxxas exchanged the system for free(wasnt bad but wanted castle). i put the castle system in the boat and havent run it but was wondering what prop i should run for speed runs and what prop for play. i will be running boat on 6s. the boat is 29 inches long. i believe i should be around 65mph for all out speed runs and 50 for playing around. props i have are as follows: x642, x645, m445,m440, m447, m545, grim L44x66, grim 42x55, grim 40x53 3 blade, grim 40x57, grim L38x63. any help would be great.