Nothing wrong with upping the dose (or dropping it for that matter). Beans from different origins & roasters will extract differently & with using a machine like a moccamaster (instead of manual brewing), your only choices of adjustment is dose & grind to adjust the speed it brews at. So long as the basket doesn't overflow (from too high a dose &/or too fine a grind), the world is your oyster.
I've never used a SGP so don't know how well it copes with single dosing. It may well work better with a loaded hopper. Either way you're better off weighing the ground coffee to make sure you're getting 60g (or whatever dose you settle on) out.