Once the professors trees are released, you might see them at the big box stores and that might be the best place for you to pick one up depending on your location, budget and expertise. In fact the only one of his creations that you might actually be able to put in your car, his earliest, "Timotoyo," has been carried by Lowes, contra the claims by the big box store haters that big box stores don't carry unusual trees or cultivars.
For the rest you can place an order and wait.
Frankly I'm surprised that I'm the only one defending the big stores. I know there are dozens or hundreds of TFF members that frequent those stores regularly and appreciate their qualities (location, price, selection, service, etc). I also know that some of the people developing new cultivars will be happy to sell their trees through those stores and benefit by doing so. And yet we all sit around and listen to those stores being trashed and say nothing? I couldn't let it go. I shop there, I like it and its a good thing. I also shop at local nurseries and that's a good thing. In my area every nursery has good qualities and things to criticize. To single out big box stores for criticism is grossly unjust.