I like this arm wrestler's way of thinking for training

[Rick Browne]

 

[Florian Kellersmann]

I can highly recommend follow Devon's advices. It works. 

[JayGrips]

i do something similar for grip.  two week of 5 sets of 3 followed by two weeks of 5 sets of 5.  thats for my main movement.  my assistance exercises i do for sets of 10 .  typically 3 movements per workout.  i train pinch and thickbar on seperate days so overall training grip twice per week