You been on the Moth a bit too much Taipanfc.... :-P

Decreasing beam from hull to hull despite the addition of wings will reduce your RM significantly. The pivot point for a cat is over the centerline of the leeward hull. By adding wings you through more beam (and weight) leeward of the pivot point. You are also brining the weight of the windward hull closer to the pivot point. Even reducing the beam by a little bit makes a big difference.

So, a Taipan 4.9 would be better investing thier money into a set of wider beams, tramp and stays, forgetting about wings.

If the class rules alowed a max beam and then wings, by all means go for it. If it is just max beam, increase the beam of the hulls.

Jump back on a cat mate, you know you want too :-) Sorry, could not resist.