After using the solar grill for a year, and seeing what worked and what were problems, I made some important tweaks to the grill.
1.The graphite solar reciever was secured, so placing the grill on a surface will not push the graphite into the grill
2. Grease from burgers and other meats were falling on the graphite, and then flowing out and dripping on the mirrors, messy problem. I made a stainless steel holder for a standard 8" aluminum pie dish, which works great at keeping things clean.
3. Made a new solar pressure cooker, with two covers, one lets it work for cooking, the other has steam gage and copper steam line so we can use it to make distilled water, or run a small steam engine.
Continuous improvement, so every year it gets easier and better.