Nice Pe but have you taken any temp readings to show exactly what affect the baffles have made? With all my cowled models I've always tried to make them a close fit around the cylinders but left the head out in the airstream. It seems that may not be the best way to do it.

One simple trick that I've read about is to have a triangular shaped extension from the firewall up to the back of the cylinder. This normally has stagnant air in that area because of the flow around each side meeting up at that point and just swirling around against the flat firewall instead of escaping and carrying away the heat. The extension keeps the flow seperated and directs it out each side.