Remember the elevator is in the front, so the forward the CG the less stable the plane would be. The same when the elevator is in the rear the aft the CG the less stable the plane. The close the CG to the elevator the more pitch sensitive the plane is(until certain point of course).

I have not fly a Long-EZ carnard but I used to fly a Firebat carnard, I'm talking by experience. I like to experience moving the CG a little at a time will not cause "serious flyability problems". Also the long take off runs could be attributed to a nose heavy condition.