There used to be people growing it in FL but it's said that they used seeds and they turned out rubbery. Maybe they're from inferior seedlings from Japan back then.
I have my 1 plant in ground but attempts to airlayer failed for the past 2-3 years. I'll ground layer next.
Myrica cerifera is said to be a good rootstock for it. Someone in norcal grafted to it and the grafts are still doing well. M. californica also works.
I got some seeds from a forum member and was successful in germinating most of them. Unfortunately it was a test and I didn't put them in soil. They then grew mold and rotted. I still have a few seeds that I will try in soil. The trick is to get the kernel out of the thick shell in one piece so the inhibiting hormone will dissipate. The thin skin on the kernel also inhibits but it's okay to leave it since the difference is not as much as taking it out of the shell.
About 1/4 of seeds will have aborted kernels. So that contributes to the known low germination rate of these seeds.