If you like the SDB, I'd try to fit an add'l. press dedicated to the 308. Lee offers a kit so each press is mounted to it's own board and each is changed out with just 4 bolts. They also offer a reloading stand.

I'm a big fan of turret presses myself, never used/needed a progressive. Since you already have the progressive, I would opt for a dedicated press for rifle cartridges.