Infinity worn by sorc

Hey there!
I’m running a novasorc with all bells and whistles.
Full inv. of lightskillers+griffons dual SoJ and so on.
I decided to let my merc run Insight and build an Infinity (´-51%light res) in a Scythe and wear it.
I feel like a semitruck plowing through stuff but I’m not quite that its THAT much better other than the fact than I’m invincible with ES.
I’m running with 105FCR atm.

Does anyone know the maths here? Is it really better dmgwise or?