Red,
I would mount the ESC just like you have it, but on the bottom of the cowl.

I have a question though. It looks like in the middle photo above you blocked the airflow. I am missing the point of this. You need as much airflow across the motor and batteries as you can get. Especially since you are running such high amps. You exit hole must be twice the size of the entry hole to creat a vacume effect to force cool air in and warm air out.

Thanks for sharing the conversion. I have followed Norm's, but it is good to see another.

-Mike