You want a bench top that is very rigid such as one with a 3/4" plywood top and a 2X4 or a 2X6 on edge framework underneath. For years I used a flexible bench top and was always cursing it. But no more, 10 years ago I made a proper bench. The top needs to extend beyond the front of the bench slightly to allow for the articulation of the press's toggle. Some presses require a bit more length than others so measure the maximum articulation the linkage makes behind the press to determine the overhang of the top. I inlayed a steel plate across the front of my bench and welded bolts to it to hold my press. This is a pretty good way to stiffen up a bench, but it makes attaching the press a bit more work. A thin piece of plywood is placed under the press to make up for imperfections of the casting against the steel plate. I prefer to stand when I'm loading, so my bench height is 4". The legs are 4X4s, there is a lower shelf to store stuff and upper shelves for bullets, an eye level scale, and storage for the dies , etc. I kept the depth of the bench fairly shallow (2') to make reaching to the back easy. The lower shelf is also 2' and the middle shelf above the bench top is 1" and the top self is only the length of a die box, 6.5". The plywood backing stiffened everything up nicely, and I installed a top over the work area and mounted a 2 bulb florescent light fixture to it.
