MSoZ upgrades ?

Hello,

Wondering how to further upgrade my MSoZ, this is the current variant:

https://poe.ninja/poe1/builds/keepers/character/bathristowow-6109/Big_Fucking_Fiery_Balls?i=0&search=name%3Dbig_fuck

I'd like to get more tanky while keeping the DPS that I currently have (or increase it), I know that I can go for forbidden flame/flesh, but that seems to make me lose more than gain ? not sure, thx for the advice.