What are your favorite treats to use? Which brand/size works best for you, or do you make your own?

I've always fed the manna pro horse nuggets, but I heard someone say they were too large to use for clicker training. I'm gentling my first feral mustang & I wanted to use clicker training with her, so I was going to buy a big bag but I don't want to buy the "wrong" ones so to speak.

Would love any recommendations (or recipes!)