That's not entirely correct Darryl. The positive effect of weather helm is real but not because you point higher to windward, you can't point higher without luffing/pinching the sails.

The reason a bit of weather helm helps windward performance is because you need to correct it with your rudder, otherwise you'd continue to round up into the wind, which we know is slow.

The force you feel on the tiller while holding your boat on a steady course (preventing it from rounding up) is caused by a force on the rudder blade.

This force on the rudder blade is pushing you to windward, which is good.

If ppl can't picture it, try experimenting on shore with the skipper sitting on the boat in the usual position holding the tiller extension so that the rudder stays straight and have the crew push on the leeward rudder box.

So instead of pointing higher, you aren't slipping sideways to leeward as much, which increases your VMG.

But hangon, having pressure on the rudder is slow because it is drag. The trick is finding the right amount of weather helm so that you provide some lift force to windward to reduce leeway angle but don't increase the drag caused by the rudder being off centre too much.

It's a tricky design problem but can be done fairly easily by trial and error by adjusting the rake and testing.