I'm in Australia so we run pretty much the IFMAR rules.
It is just interesting that the top guys run with the smaller 50mm hole above the fuel tank and the side windows cut out, I have set mine up with the 60mm hole in front of the engine and still have good access to the fuel tank but i will be trying the side window cut outs as well next week to see how much more cooling this adds.
It would be interesting to see where the Body manufactures have the hole cutouts located when doing the air flow modelling when designing the body or is this why the top guys run the bodies like this.