Your best bet would likely be to stick with the Woollybugger since you've confirmed that they'll eat it, and experiment with the presentation.
Now that I've said that.....I'll tell you about the fly that always comes to my mind when someone mentions cats on the flyrod, Some company used to (and may still) make a thing called "nymphform", it was a spear shaped piece of plastic that carried just enough weight to sink itself slowly. It was lashed onto the hook and gave a flattened profile to whatever pattern you were tying.
quite a few years ago myself and a flyfishin'buddy discovered by accident that a nymph tied with one of those on a #8 9671 Mustad, with short stubby split-biot tails with a body and thorax of black rabbit dubbing, ribbed with clear mono...was a killer on the cats in every pond, lake, and strip pit we fished at the time.
We would cast parellel to the shore on the steeper banks and consistently catch little 1-2 lb. channel cats if they were cruisin' the banks during mid-late Spring. Nothing special or fancy about the tie, but the best retrieve was always a slow figure 8 hand-twist with frequent pauses. It caught quite a few bull bluegill also.