This "unstable" refers to the location of the c.g. It was placed further aft than one would do normally. Moving the canards up (or down) won't have any effect on the stability of the plane.
A model would need to be automatically stable, with the c.g. forward of where it was on the full-scale.
Otherwise, it would fall into (drop into, stall into) the cliche, "..tail heavy models fly once..."