Glad to see you back at it. So the shoulder has healed somewhat?
The motor baseplate is steel that you've fab'd up? I'm always more surprised I can weld to old mystery metal than not. So the idea is the motor goes in between the 4 angles and then you're going to use like a hose clamp around them to clamp the motor in place? Should work, might even act like cooling fins if you can somehow get some airflow in there.