first things first check the perks
breathless - neutral, doesnt really help that much right now
homing - this seems good but i rarely ever take it because theres a ton of cases where you dont actually want your shots to automatically home in. and homing is a modifier that you can put on a wand yourself. if you took the rock wand from the fungal above like i showed and then took this though thats an amazing one spell one perk combo that destroys the entire game
and last is exploding corpses - effectively this is explosion immunity with the downside that you will now have to dodge fire all over the place. the upside is you never have to worry about explosion damage again which means hiisi base is mostly free since the only actually dangerous shit in there are the hidden propane tanks that end up fucking you
so thats my pick, easily, no question, exploding corpses