stek79,

I think I see what you are getting at but I think you have the wrong sense of the distribution?

Spiraling airflow around the fuselage presents itself to all protruding surfaces making them all see an angel of attack. This in itself is actually good. The protruding surfaces work like stator veins straightening the prop wash. The reaction is a small rolling moment towards the direction of prop rotation. This helps stay the engine torque. Prop rotates right, airframe torques left, stator action twist right.

The imbalanced vertical area in the back is what causes the yaw problems. A slight yaw is produced from the vertical fin because it only sticks out on the top side. A right rotating prop slip stream pushes top mounted fin right causing some left yaw. An equal sized sub fin is what would eliminate this. Sub fins aren't popular because of ground clearance during takeoff and landing. Full size single engine plane designs often mount the vertical fin offset left slightly for this reason. A small amount of right engine thrust can help with this, and works when flying inverted too. Thrust points the other way but vertical fin is inverted and getting pushed the other way too. Note that multiengine planes with wing mounted engines do not yaw in reaction to spiraling prop wash. Area getting torqued on is balanced.

Spiraling slip stream is only one of the propeller effects that right thrust can help. The larger reason for right thrust is P-factor at slow speed. If the prop disk is not exactly perpendicular to the air stream, the blades will see different AOA on opposite sides of the disk. This shows up the most during slow flight. Nose high attitude tilts the prop arc back causing the descending blade (on the right) to take a bigger bite out of the air, and the rising blade (on the left) to take a smaller bite. Basically offsets the center of thrust to the right causing a yaw to the left. Right thrust compensates. As speed builds and nose lowers the effect reduces and the right thrust eventually becomes a nuisance, but aerodynamic stability is much greater now. So, adding more right thrust is a good compromise – but for flying right side up only. During inverted flight the right thrust is now left thrust but the P effect is still the same.

This is why aerobatic planes usually have just a little or no right thrust, while trainer and sport planes usually have noticeably more - they just spend more time right side up and are optimized for that.

A better solution of course is counter rotating props or pure jet power. There is no way to make one prop perfect.

Multiflyer