Rules of Thumb I've used for reloading benches:
1. Make it deeper--probably 30" min.
2. Make it 36"-42" high to have the option of reloading while standing or seated.
My latest technique is to build over a 24" deep base, then put a double-thickness (ca. 1.5" plus) MDO top on it. This detail allows mounting the presses outside the base, and provides for good knee room. It allows for component (bullet) storage across the back, which will further stabilize / dampen it.
3. Make the top really heavy duty.
For my handgun-caliber and minimal / small rifle reloading, I have a dedicated bench and permanently-mounted stations.
4. Draw a plan view and sort out your workflow needs before you mount the press(es).
IMO, you want a minimum of about 12" to the left side and 18" to the right side of a given press station. This layout is based on a right-handed person handling components on the left and finished rounds to the right. With 30" or so between two presses, you will have room in the middle, towards the back, for a scale, etc.
5. Build at least one HD (2x materials) shelf above the benchtop, about 15" up-- This shelf can now hold anything from more components to your spare die sets, measures, shell plates, etc., etc.
6. Provide a "reference desk" nearby or an additional shelf at the top for your manuals, etc., etc.
My current benchtop--for reloading only, not for preparation--is only 54" long, but I can work comfortably at it with my (Lee) Turret mounted on the left and my Load-Master mounted to the right. Were it about 72" long, I could have a SS press mounted as well, I think--but since I can use the Lee Turret as a SS, I really don't need it.
I have the HD shelf mentioned, and another shelf above it, with the gear and books stored as described. I keep Lee measures 'ready' to go, with holes in that lower shelf to receive the drop tubes. The turret / die sets sit next to them. There's just room in back benchtop middle for my scale, which is set up to work with my bifocals and my aging eyes.
Consider all the angles--and plan, plan, plan. Ask questions as you need--describe your planned reloading completely, and a layout scheme will start to emerge.
Jim H.