How did everything else come out? If you built it without the calculator in the first place it is important to know how far off everything is and how it cooks so we can do some troubleshooting with you.
I went by Feldon's calculator but had a problem understanding it. At first it it was way hotter closer to the fb but I put some defussers across below the grate and was able to level out the temperature across the grate. Almost all the way across.