I fish the gizzit as well in the brown root beer color, but I'd definitely recommend the 1/4 oz. I fish it down to 30 ft and have had good success on summer smallies, or even as they're staging during pre-spawn. I don't like the flat gizzit jig heads mainly because the hook itself is pretty weak. Standard tube heads seem to spiral down alright for me.
If you push the eye of the jig head further back through the plastic, closer to the tail, you'll get a wider spiral. Closet to the front of the bait produces a tighter spiral typically.