I am putting together a reloading bench. The base is built, glued and screwed and braced. I have a piece of maple from a bowling alley for the top but have not yet attached the top. For some cartridges I use a Harrell's press and hand dies. It that mounts to the top with an integral clamp which needs about 4" of overhang. I will also be using a 550 and occasionally a Rockchucker. I have Ultramounts for both. Any reason to have more than  4" of overhang on the front?

Any other ideas how to mount the presses? Maybe something modular?

Thanks!

Inline fabrication  makes quick change mounting platforms in three different heights. I use a medium height which I use for a press, trimmer, and vice.

I would think that 4” of overhang would be plenty.  

Just make sure the rear 2 bolts on a mounting system don't end up where a base support is located. Should be fine with Inline Fab mount with a 4" over hang according to these templates: https://inlinefabrication.com/collections/quick-change-press-mounting-system

I used a Lee bench mount system and a rockchucker fits, just barely. 550 would probably need a larger mounting system.

10-4

This is a good point, figure out what equipment you're going to mount before deciding about the top, since you can. E.g. Might you ever mount a basic vise to this bench to hold stuff while you work on it?