I recently started doing a 5x5 for my standing arm curls with the zig zag bar.
I then do preacher curls 3 sets of 8-10. then 3 sets of hammer...? curls, the ones with your palm perpendicular to the the floor 3 sets of 8-10.

the werid thing is my left arm is bigger and I'm right handed.

I guess the right is just trained more for endurance (smaller longer)
and my left is only used for lifting, so it's trained for power (larger, more peak)