Thanks for the advice. I get beecraft and have the article I am still unsure about what size/grade of screen and what material. I obviously don't want the Virgin Queen to travel down into the bottom boxes. Cushman made his from stainless steel, others use mild steel, some plastics, and some have heat/food exchange mesh. Also there are even double ones that could be used for Twinstock. I am however determined to make my own, I am going to borrow a friend's Stamfordham one as a template.