Very interesting, good threads, thanks.
So ... according to Williams' speculative ideal WWII single-engine fighter armanent, best arrangement would be one 30mm cannon firing through hub plus two 20 mm cannon in wing roots (vee engine) or two 20mm in cowling and two 20mm in wing roots (radial engine), requiring synchronization for all.
And twin-engine fighters provide best choice of all with no synch problems in clear nose.
One other question which am still uncertain about -- does Aces High model synchronization? I assume not, and this could make a big difference since synch apparently reduces rate of fire 10 to 50%.
If synch not modeled, are guns that fire through prop reduced in fire rate to simulate the lesser firepower?
One other nitpicky question: is the fire rate reduced in any way of a cannon firing through the prop hub or is the rate just as free as a clear nose mounting such as on a P-38?