I have done it. I have figured it out; the secret formula.
This is the ONE thing you MUST do if you want to improve your handstands. Many people stunt their own progress by not utilizing this powerful tip.

In the spirit of the holidays, I will be giving out this valuable information for FREE, but for a limited time only.
Can you guess this ultimate technique? No, it's not more hollow body holds.
Try again. No, shoulder stretching is not the answer.
More props? Band assist? Core Strength? Pelvic floor activation? Steroids? Certifications? No! WTF is wrong with you?.

Here is the ultimate answer, the secret formula:
Do more handstands.
Not what you expected? Or maybe not what you hoped. Practicing the skill you are trying to get better at is the only way to directly improve.
Can't do a handstand yet? Good, potential for more improvement.
So, what makes you think hollow holds and shoulder stretches are going to get you closer. If your HS practice does not mostly consist of handstands, you are doing something wrong.

What if you have a banana back? Then it's clear you have brought shame upon your family name and must never speak of this again. Seriously, it's ok. This may not be the ideal textbook HS position for modern standards but there is no need to vilify it(especially since it's an important part of the history of the skill).

Don't get me wrong, all this other stuff is important. Strengthen your wrists, stretch your shoulders, work your line, etc. Stop chasing quick answers when you know what the real solution is. This is a skill. You're going to suck, maybe for a while, maybe for ever. In order to suck less you have to put in work over time.

Happy Handstanding