Steven,

The engine I show is without piston ring and for that reason I will not change the exhaust position after running,
I do no know about the ringed engine to change the position if possible.

I use Fuel with 5 % nitro syntetic oil but the engine is without ring, so I think a modern engine when we compare with yours!!!
We have to know that for sure!

I always use the muffler pressure and a checkvalve to have the max exhaust pressure of the muffler in the tank.
I do not know if this pressure is enough for you, but you can try on a bench, put the tankposition on the low level just like the nose up position of the plane. So the same vertical distance

The muffler tap I do find the best for me, simple.
Be aware of the pressure of a crankcase tap, that can be 7 psi I think! and for sure when you combine the crankcase tap with a checkvalve. These pressure I do not like in my tank in the plane.

I never use a tank in CG position. If you do you need a pressure in the tank to get the fuel above the engine in nose up position and also during iddle, that's the reason of my chackvalve.
Let it be clear, I do not use the tank in CG, so maybe there are other pilots with experience to tell us the facts.

I can put my plane in any position without any influences on RPM even nose down.
Nose up the "trapped" tankpressure by the checkvalve is enough to get the fuel above the engine and the regulator does reduce the pressure to barometric even with nose down of the plane. That's the way the Cline works also.
The little brass tube near the carb of the engine is the pressure measuring tube for the regulator beside the engine. This way the dynamic + static pressure of the regulator is the same as the air inlet of the carb.
(The plastic tube is the cold junction of the thermocouple of the engine temp measurement)

Cees