(During this time period, I went from a shitty 5 second HS to a 65 second handstand, and also achieved the straddle press handstand.)
By quality freestanding handstand, I mean a pointed toes, well -aligned, ribs in, locked elbows, elevated shoulders solid handstand that you can hold for 30-60 seconds.
There are 1,345,983 handstand exercises posted online. Ignore 99.9% of them. Less is more. Pick the high yield ones as posted here.
First off, it's NOT about balance for quite awhile. It's about strength. So start building strength, and then we will worry about proper rebalancing exercises.
2 drills for you to get going:
A. First knuckle raises: a few sets of 10-15 reps, make this hard work for yourself: https://vimeo.com/154205949
B. Chest to Wall Handstand: build up to where you can hold this for 60 seconds for multiple sets. This video has a link to Ido Portal's blog on the subject for further reading.
If you want to make progress, work on handstands at least 4x/week.
If you really want to make progress, hire a teacher who can program the proper exercises and volume for you. But this is a great place to start laying the foundation.