I generally deal with Aquarius, off HWY-1 at Del Monte, in Monterey, though don't quite know what they have in their rental fleet, and frankly don't even know what a "semi-dry suit" happens to be (what -- is that like semiautomatic or semi-pregnant?). Any decent-fitting 7 mm wetsuit should just be fine, while actively swimming, which is what I typically use, since my current drysuit has a zipper across the back -- yeah, there's a brilliant gaffe -- and is a drag to use, if diving solo, which I frequently do . . .