Right now the plan is to do some grafting onto some Chinese seedlings that I have. I have some Buck IV trees that I grew from nuts three years ago and I am planning on taking some graft wood from them. May try to do a little nut grafting as well. My Buck IV trees are still too small to produce nuts right now so I do not know if they are in fact late dropping yet but I'm betting that they are and would like to get a early start on propagating more of them.
You mentioned the 3D printed containers. The containers did great. However, I didn't do so great with my seedlings this year and waited way to late to remove them from the containers. Those that made it will be planted in the field this year. I grew so many the couple years before I just got burnt out from the amount of work it took just to keep them watered and my seedlings suffered because of it. Also, tired of seeing all my efforts go up in smoke due to our hot weather here. So my efforts have turned to saving what I currently have and focus more in direct seeding going forward. I think that will give me the best chance of survival in the hot Texas sun.
The growth rate suffered when I didn't move them into a bigger container. Basically I had some seedlings set the whole summer in Rootmaker 18s. They got to a point to where the root system couldn't support any more top growth and basically just stalled out. I'm sure they will pick back up next spring but I lost some growing time this year and they aren't nearly as tall as they should be for one year seedlings.
The more I try to grow trees in the rootmaker pots the more I'm convinced this may not be the way to go if you live in a arid climate such as Texas during the summer where it isn't uncommon to go 5-6 weeks without rain. The root systems, while healthy and fibrous, don't have the tap root necessary to seek out water deep underground. If you grow rootmaker trees here be prepared to baby them for at least three to four years upsizing the pots each year to give the trees enough time to develop a large root system before planting them in the field. If not, be prepared to water weekly during the summer and if you have a large amount of trees that will get old real quick!
Direct seeding will allow the tree to grow with the tap root intact so that it can grow deep underground and hopefully seek out water. You'll still have to supplement water during the summer but not near as much. It has also been claimed that direct seeded trees will catch up to their rootmaker grown cousins after 4-5 years of growth and be virtually identical in size.
On the other hand, there may be a reason why Chestnuts don't grow natively here. Its just too dang hot!