Ring Handstand Frequency?

I recently moved back home from Texas to Florida, and I was able to hang up my homemade rings to a tree branch with about 12-14 feet of strap length.

Because of the new length, I now have room to do handstands on my rings...

I use adjustable straps and keep the rings as low as possible for whatever exercise I use, so I kick up into the handstands.

How frequently should I be doing handstands on my rings for optimum benefit?

Currently I've been exercising on a MT TF schedule, and doing around a minute total in handstands.

Is this good?

Yes, sounds pretty good. One minute isn't a lot of volume so this shouldn't be too hard to handle. Add more if you like and have no problems with recovering from it and the other part of your workouts.

I have one more question... how long should I be able to hold a handstand on the rings, before I would be strong enough to do a handstand push-up?

Is there a typical correlation, like, if you can do a handstand push-up, hands to shoulders, you can also hold a handstand for ... two minutes?

Just curious if there is a way for me to know that I'm ready, other than trying it out every couple of weeks.

No idea. work the shoulderstand and then climb with your legs up to HS. Practice lowering to shoulderstand in negatives.

You could also just do part of the HSPU, and every so often add another inch to the ROM.