CT, I have never had rear delts, and shoulders in general are something I have struggled greatly to bring up. Ive tried to focus on them lately by playing with my face pull form, but with limited results.
However, adding the squeeze/pause at the full contraction of my pulling exercises, especially one arm DB rows, over the past month or so, has really brought my rear delts into the equation, almost to the point that I cannot follow a day of heavy db rows with a day of heavy push presses because the presees feel less stable when my rear delts are trashed. I think its even partially that my form has improved to accomodate the squeeze at the top, and then the eccentric is wonderfully brutal because I have never felt my rear delts so well.
So, thanks for the reccommendation and if anyone else has shitty rear delts like me (I have eyes and know Im not alone), maybe try this out.