q = 0.14: S_2/S_3 = 0.94941, S_4/S_3 = 0.99304
sign +1: worst relative margin -0.00156 at a1 = 0.5738, a2 = 0.5738
    margin -0.00156  a1 = 0.5738  a2 = 0.5738
    margin -0.00018  a1 = 0.5738  a2 = 0.5312
sign -1: worst relative margin +0.00604 at a1 = 0.1000, a2 = 0.0385
