As a lifter that has curled a few kilo's I think less training is more.
For me, I curl once sometimes twice a week. Rarely do I go over %85 for 3 reps, one set.
Here's how it looks:
185x2 this is %85 and I don't do this set every week
I follow this with heavy hammer curls, 3 sets.
About 4 weeks out I cut out a lot of the reps and go to sets of 3 and 1 and go lighter on the hammer curls.
Just one old man's opinion.
Eddie~ AKA "Sasquatch"