i used to be well into my chining,,,,,,,,, they are in my opion, the best width exersize u can do..
best tip i came across for rank begginers and those struggling to get into the propper rep range is,, rest pause.. just pick a number and make sure you get to it,,
start with 25, your 1st set u might only get 6 or 7, just keep on going till you reach 25,, keep raising it each week..
obviously once your advanced, you can knock out 12 to 15 slow controlled reps, with big contraction at the top,,its time to start adding weight..
v bar narrow grip chins are vastly under rated too, they will give you the best lat stretch youl ever feel, make sure when u pull up, you pull to your lower chest