While I understand the reasons for the fuel tank and servo placements, the following is for anyone else who is reading this thread that's in the process of building a Northstar...

The movement of the tank is, in my opinion, not needed. With the tank in the nacelle I have never had a problem with trim change during a flight, and the addition of a pump adds some degree of complexity and another place for a fuel system problem.

The placement of the elevator servo in the nacelle is also - again in my opinion and after having built four Northstars - not needed. First of all, proper support of Sullivan Gold-N-Rods keeps the elevator control surfaces completely tight and with absolutely no slop. See pictures for a way to ensure this as well as a similar way to eliminate rudder sloppiness. As with the movement of the engine and addition of the pump, the running of long servo leads from the front (nose) of the plane to the nacelle adds a level of uncertainty due to the length of the wiring, connectors, etc. In addition, whereas the radio compartment of the plane – the cockpit area – is pretty much water tight on my planes, the nacelle area isn’t and when/if the plane is dunked the servo in the rear will get soaked.

But, if it works for you, fine. As I mentioned in my earlier post, if your plane is at or above 7# it’s heavier than it needs to be. Hope you get it off the water.