Hello all, new to the forum, I can't seem to find an answer so this is my first post.
My family owns a bison farm, typically to harvest an animal I've always used a 30-06 with 180gr core lokt psp between the eyes. I've decided I don't care much for the factory loaded core lokt anymore and now that my reloading bench is up and running, I'd prefer to load my own ammo.
My initial thought was to go with something similar to what has been working for me, so I got 180gr interlocks, but I thought maybe there is something better for the job. So a few questions.

What bullet is best for penetrating the skull and dropping the animal in one shot?
Should I stick with an exposed lead tip like interlocks? All copper like a tsx?
What is your go to load for the suggested bullet?

Rifle is a savage 111 trophy hunter, 1:10 twist
I have IMR 4064 and 4166 on hand
As for bullets I have 180gr interlock and 168 berger vld hunting

I want to know what bullet is best for my application without sacrificing accuracy. I am willing to get different powder and bullets if something is better suited to my needs. Shots will likely be taken within 20 yards, but I would like accuracy at longer range just in case. Thank you for any info guys.