82 gpz coil brackets keep breaking. ideas?

So this is 3 now that have broken. I bought some used parts from another guys and I see it came with 2 broken ones as well.
So I guess these tin brackets are a weak point?

Any one make a good aftermarket mounting plate you guys know of?
I just banged a quick aluminum one out but that might not be the best material.

This is for my S1 rep, but I see the real S1 mounted the coils under the seat and used long coil wires. wonder why?
And If I do that would I loose anything adding longer wires? Thanks for any answers.

Here's a pic of a stock one that is not broken. And the S1 setup. Also a pic of my bike:

Mounting the coils under the seat would put them in a cooler spot. The S1 seems to have an aluminum mounting plate, so I guess it is fine. wouldn't the aluminum draw heat away from the coils more quickly?

To mount Dyna coils to my 81 KZ650 I made brackets from angled aluminum from the home depot. bolted to the stock brackets.

first attempt. 1-1/2" x 1-1/2" alum bar.