My preference is Gidley at hooker with Mullen and Stig in the halves aswell (not that I think it will happen) but sj18 brings up a good point.
Gidley has trouble staying injury free these days and that's when he's playing at fullback not having to defend much and in the halves where he's defending out wide. Playing hooker where he's in the firing line in defence and having to make 30 odd tackles a game takes a toll on the body, more so then playing in the halves and at fullback IMO.
In saying that I don't think that should be a determining factor where he plays next season. We should name the best team possible and the team that will give us the best chance to win, but never the less it's a good point to raise, and having a healthy Gidley on the field regardless of position does that. He's no use to us on the sidelines come game day.