I have native persimmons growing wild on my farm. I typically wait until they are about 1" in diameter. Here they generally aren't producing flowers or fruit until much larger. I don't wait to sex them. When they hit an inch or so in diameter, I bark graft them with female scions. I'm using both named varieties, scions from some of my best producing native trees, and scions from native trees from others that I've traded with. My objective is to get persimmons dropping across a wide time window.
I only work with American persimmons because the are astringent which protects them from climbing critters until they are ripe, and they fall from the trees where deer get a fair crack at them.
In my area, native persimmons typically take 10 years to produce without grafting. If you have a small seed planted tree that is producing, that is unusual and may be a great tree to use for scions as they become available.
Thanks,
Jack