I love Push Presses, and strict Overhead Presses too....but when i start hitting a wall, here is a little trick I do for a few weeks, While standing, do one overhead press, followed by one behind the neck press, followed by one ohp, and so on until you do 4 of each for a total of 8 reps.....use a full range of motion and do 4 sets, after this do 1 set of plate raises to failure, 1 set of 1-arm d-bell raises to failure, and 1 set of reverse pec deck to failure, if you have anything left start banging out some d-bell upright rows and then see if u can even drive home.....give it a try, I do it as a break from PP and OHP to up my numbers when they stall, but also, I noticed my delts grow basically before my eyes when I do this.