Personally, I enjoy leg days more than anything. Maybe it's because my legs respond very well to training. Maybe that's the reason why I'm able to pack on a lot of mass in a short period of time. I never really tested myself for maxes once I got out of school. They're kind of pointless for anything other than bragging rights. You shouldn't be getting anywhere near your max until the end of a 6-8 week strength program.
Along the same lines, building the rest of your body will make you powerful instead of just strong when you push things. When you pick something up that's kind of heavy, do you just use your arms or do you use your back and legs too? You need to do all of it every week...with whatever program you're on.
Oh, a good exercise for delt's is lateral raises. Those'll make your shoulders look wider because they hit the middle head of the muscle group. But you'll look funny from the side unless you build up the back and front heads too. The front builds with benching and the rear builds with rows and behind the head military presses.
Increasing a max takes a long time if you do it properly. A lot of people plateau prematurely because they lift wrong.
Good example here. Its all about functionality when you're 40 or 60years old, not just how you look with your shirt off at 25.
I won't knock your information here, but I'l alter it slightly.
There's huge arguments between researchers regarding targeting muscles, muscle heads, and specific parts of the muscle. Research right now shows that even though you may feel one exercise in one area of the muscle more than another, that there's still only one insertion point for the muscle and as a result the muscle is exercised as a whole and not individual parts. No one really knows for sure, but thats what the current research shows up until atleast a year ago when I stopped eating and breathing the topic.
And behind the head presses tend to put a lot of stress of the shoulder capsules and there's no real benefit to do behind the head presses rather than any other kind of press, so go with something safe like a barbell military press infront of the head or dumbbell shoulder presses that are in line with your shoulders. I have sensitive shoulders so I notice this sort of thing specifically and I'm super careful about it, especially because medical science hasn't quite learned how to rebuild a shoulder, knee, or lower back properly yet so these are all areas that you must be really careful with lifting since there's no "cure".