I'm trying to wrap my head around a seemingly simple problem. I regret it has nothing to do with WOODEN boats, exclusively, but I hope you find it interesting.
Consider a boat like the J-29 (fiberglass, sorry). It has been built in both fractional and mast head rigs and I have read that the mast head rig is faster. If you look at racing fleet pictures, the mast head rigs outnumber fractional rigs 10:1.
Coming from dingy racing, the fractional rig is a very big deal and allows you to tune the sail shape. Obviously, boats too big to bend the mast make this less useful, but a 29 footer is still small enough to bend the mast when the wnid calls for it and sail the boat like a dingy.
I suppose the mast head rig has a bigger genoa and spinnaker, but sail shape is critical to speed and pointing ability.
So, why do mast head rigs appear to be faster?