The loading issues that are referred to above are not due to the aft-mounted engines - there's no reason why that configuration should be more or less easy to keep control of the cg.
Why not?
Look at an aircraft with wingmounted engines. The CoG is around wing, as it needs to be in flight. The engines are near CoG. The fuel, in wing, is near CoG. The fuselage structural weight is distributed fore and aft of wing. The payload is divided between fore and aft fuselage. The main landing gears can be slightly behind CoG.
Now compare a plane with tail engines. Since heavy engines are far from CoG, they must be counterbalanced by long forward fuselage. But now, since mose payload volume is ahead of CoG, the centre of gravity moves when payload is removed, which is not the case with wing-mounted engines.