While it doesn't count as a light weapon, with this combination of feats you could use a Spiked Chain as your primary weapon and a light weapon in your off hand with -2/-2 penalties. Or a spiked chain in each hand at -4/-4. Or a single spiked chain used TWF at the same -4/-4.
An Effortless Lace may work since chain mastery allows chain spikes to be treated as one handed for all purposes which might include use of the Effortless Lace.