I find putting Hogue G10 checkered grips on my Sigs makes them work vastly better than the OE poly grips. The Hogues are much flatter on the sides with larger radii around the back. The OE poly grips are more ellipsoid in cross section, with curved sides and a smaller radius at the rear. You should try a set of Hogues on that 228.
I always love the slimness of a 1911, but the grip just doesn't work when I take hold of it firmly to actually do some work with it. The Sigs with Hogue G10 feel customized for my hands. I'm thinking the SA-35 might provide the slimness and balance of a 1911 with a grip that's just right.