slow negatives on deads must be a real bitch
I believe Mentzer stated somewhere that rest pause is best with push exercises, mainly chest and delt work
I used to consult with Mentzer. I truly don't think he had any better routines than Heavy Duty II. The consolidation routine was too little in the way of exercise, and would lead to deconditioning. I remember one guy on the boards (Jammin' Jake Sands) used to train once every 5 weeks with this routine. No, I am not joking.
I had figured out doing slow negatives on deads was a great way to train for quite some time prior to my consults. Turns out Vince Anello was training a 6 second negative for many years. There is nothing new under the sun. The answer is to train briefly, intensely, progressively and consistently if you are natural. Your results will speak for themselves. And if you are something short of a genetic marvel, you will be better than most of your friends, but will not look like Mike O'Hearn, Skip LaCour or Jeff Willet.
I had one friend who had the genetics of a Casey Viator (huge forearms and calves) who remained natural. Very impressive, but was never cut or stage ready. Me, I vastly improved from where I started, so I was/am happy.