Yeah Brandon I am curious my self.
I looked for cast iron type grates and couldn't find anything that was close to the size I needed.
RileySugarbush gave me the idea to fab a set from 1/4" steel angle.
We'll see, if they last only a year or two that won't be too bad. I think I spent something like $10-15 on the steel.
I did get to work on the evap this evening, I think I got everything fab'ed and trialed fitted. I had to take everything out to fire caulk some of the seams. The fire caulk is rated to 1000 deg so I am hoping that being behind firebrick it will help to protect the caulk from burning out too quickly.