i have read many articles on the highly debated breathing squats routines
...
i'm 23 now and my growth has peaked at my towering height of 5'9"

so my ribs are pretty much set in stone. the one area pullovers do seem to hit though are the serratus muscles
1) I tried the breathing squats routine for a short while. I would do 20 rep sessions, adding weight each session. Unfortunately, time and events caught up with me and I was not able to finish (that happens to me a lot...).
I can note however, that the main emphasis of my "breathing squats" was the breathing. I was made to feel as though my chest and lungs were being squashed because of the length of time the heavy bar was on my shoulders. The exercise may be profitable for endurance, but for me it was frankly a distraction in terms of either strength or hypertrophy.
I agree with the principle: high reps, heavy weight, progressive load. However, I think you'd be much better served to use Max-Stim rather than breathing squats. Max-Stim also requires high reps, heavy weight and progressive load, but it allows you to focus on the lifts rather than on the breathing. Max-Stim also allows for much better control of fatigue.
2) Don't knock 5'9". I stand 5'2" and would give a lot for another half foot of height. Three of my five sons are 5'10". That's plenty enough to get by with.
You've only got just so much life energy. You can squander it on height, or spend it on intelligence and good looks...!
3) If you want to work your serratus muscles, you can to a serratus press along with your bench press. You've already got the bar overhead, so it only takes another few seconds.
Serratus Press