F2 = - F3 implies that q1 = - 4 q 2
Fx = Fy = [ 1 / (4 pi epsilon0) ] [ q2 / L2 ] [ 1 - sqrt(2) / 4 ]
|F| = [ 1 /( 4 pi epsilon0 r2 ) ] [alpha Q (1 - alpha) Q] which is maximized when alpha = 1/2.