Tabata Overhead

I really need to get stronger overhead. My limitations are based somewhat on shoulder angle and position, although that has improved a ton since PT. Besides positioning, I'm not sure why my overhead strength is stagnant. I was looking back and my current 5RM on shoulder press is the same as it was in January. That is frustrating. In an attempt to jumpstart something, I doubled up Tuesday and made up a tabata style WoD
20 seconds on, 10 seconds off for 8 rounds each of the following exercises:
pike HSPU
wall ball
45lb shoulder press
handstand holds

I didn't keep score because I was on my own and that would have been too tricky, but here is how it went generally:
pike HSPU: I started with Aubri telling me when I was vertical (then she left) and trying to maintain that the whole time. My pike was at first on toes, then I had to shift to on knees to keep progressing with reps. I know my shoulder angle closed a bit with fatigue, but I fought for an open angle.
Wall Ball: Not too hard by itself, but tough after the HSPU. I averaged 10-11 reps/round initially with a decline to 8-9 by rounds 6-8. I have a black ball and it was dark, so this got tricky. I also just threw it up without hitting the wall, but I knew about where 10 feet was.
shoulder Press: I started with a push press but that let my shoulders off the hook too much. I changed mid first round to shoulder press to work on just shoulder strength. I tried to focus on tight glutes and abs and efficient movement. I still feel like the bar travels in an arc, rather than straight up, but it felt better with time. I averaged 9-10 reps per round with this. This was definitely the final straw for my shoulders.
hand stand holds/pushups: I tried one time and almost gave myself a C2 fracture when my arms collapsed. For safety reasons I went with pushups. I made it through 4 rounds with reps declining from 11 to 4 over each round. I decided that, when I can't muster even one pushup, it is time to be done.

This was a different type of tabata. It wasn't about volume as much as it was about muscle fatigue. I wasn't gassed at the end, but my shoulders couldn't do another rep of each of the exercises in each cycle. I expected some DOMS this morning, but none. Either I am getting good at muscle recovery, or I didn't push hard enough last night. My reps were truly limited by muscle failure rather than endurance. When you can't get your self up for one more HSPU, there is not point in struggling through a half rep and destroying your attempts for the next round of 20 seconds. I don't know if this will help, but I have to do something to jump start my overhead strength. We'll see if this helps.