How does this heater box retainer rod (J-hook) work?

[Dartswinger70]

I repaired the inside and outside of my heater box with JB Weld. That has held up great. I believe I used a large washer to distribute the pressure from the J hook on the bottom. I also used a couple of washers to reinforce where the heater box attaches to that part of the box.

I was thinking of using a fender washer on the bottom side ti distribute the weight also. Sounds like a good idea.