On the other hand, most profile 3d planes mount the tank with the rear of the tank just in front of the leading edge of the wing. I fly 3 profile planes that way and they work fine.
A typical 40 size 3d plane will weigh 50 ozs and have the cg about 5 " aft of the wing leading edge. Let's say the tank is 4" long, holds 6 oz of fuel and sits right in front of the wing. When I add 6 ozs of fuel centered 5" + 2" in front of the cg of the plane the cg moves forward 1". So when sitting on the ground with a full tank the cg is 4" aft of the leading edge . Just as the tank runs dry the cg is 5" aft. That is how much the cg shifts during a flight for the plane assumed. I am suprised there isn't more difference in the way the plane fliesfrom full tank to empty tank, but it doesn't seem to be a problem for fun flying. Some guys go to a lot of trouble to put their tank at the cg and it must make their plane flying characteristics more consistant throughout a flight.