I have a vacuum pump in my facility but has been used very little since I started here almost 5 years ago. I see plenty of opportunities in the products that we run but I have very little knowledge on the whole concept of making my own dedicated fixtures. My first initial question is if I'm going to hold down a piece of aluminum that is 1" thick x 6.125" x 6.75", is it best to pocket out the entire middle of the fixture out to the edge less about a 1/4" on each side of the gasket or do a grid inside that area? Is it better to go as shallow as possible for the pocket/grid or is deeper better for creating the best vacuum hold down pressure? Any help would be appreciated because I've heard two different theories. Thanks