Hi, its usual for most fast electrics to have a slight list when running straight. its caused by the torque of the motor. you can offset it but moving the battries or radio gear across the hull slightly, but as the batteries run down the list will lessen. Its just a matter of experimenting. I usually try to adjust it so the boat runs level when half way through your total run time, i find this to be the best compromise.
what appears to be the trouble with the water cooling, is there no water flow, or is the cooling not effective?
i wouldn't give up on this hull just yet, all performance boats take time to evolve to the maximum potential, thats half the fun!!! & what you learn from this project can be used to help avoid mistakes on your next project. (hopefully)
post some pictures if you are able & I'm sure the mayhemmers will help sort this hull out.
Hope this helps, good luck
Cheers Glenn