Think about the processes that will be performed, and imagine yourself moving through the space you have allocated. Try to figure out how to optimize the bench, and your position at it.
I've been working on a new bench for a while, and have spent dozens of hours planning the thing (even though it will be built from scrap lumber).
To me, efficiency is very important.
But... my basic set up includes only the following requirements:
24" bar stool (I sit while reloading)
35-36" bench height (comfortable while sitting, but still useful when standing)
decent lighting (who likes working in the dark?)
lower shelves (so I can store supplies, and weigh the bench down)
Just enough room for my press, scale, a bowl of powder (for trickling), and a load block.
To do that, I need a bench surface that's about 24" wide, by 18" deep. Anything more is just a nice bonus.
I do prefer locking up powder, primers, and loaded ammo; but don't really care about dies, brass, and bullets. My solution, however, is a locking door knob on the closet I use for storage (and another on the reloading room door).
Avoid mounting fluorescent lights close to your bench. Some scales can be influenced by the ballasts in the fixtures.
Everyone has their own idea of how strong a bench should be. Mine? Well... the right hand leg is a 1-3/4" solid-core door. But... The primary bench is a 1-3/4" solid-core door, with 2 layers of 3/4" plywood on top
. Even by my standards, that's overkill.... but it's strong and stable.
The odd section sticking out the left side was designed into the bench so I would have an easy place to clamp something to the bench, should the need arise.
This bench includes its own lighting, has 6 planned outlets (4 switched), and has under-bench lighting (not shown).