Almost all the rigidity in a pipe is its outer most wall. Too thick and it will sag under its own weight. I spent a lot of time choosing the EMT. If you are concerned you can use supports midway on the outer most rails. 1 support midway increases rigidity by 4x’s (if I remember that class right). the best way to increase rigidity is to use a larger diameter tube….not easy in our case. also careful of surface finish and dimension.
This also depends on what you plan on cutting with it. foam, wood, plastic, metal.