Hope you're well!
I never did end up finding out which cultivars to get - all of the info I could find was primarily about the nut characteristics - nothing about shade tolerance of specific cultivars or anything to that effect.
I did, however, rule out Chinese due to their necessity of high heat to ripen nuts. I'm planning to stick with European and European x Japanese Hybrids.
I would have simply gotten them all, in that case, but chestnuts are notorious for their grafts failing after a few years and a once healthy, happy young tree dying back and reverting to it's rootstock.
However, I DID find a solution that works for me - I was luck enough to find a local chestnut orchard with lots of mature European chestnut cultivars, so I bought about 30 lbs of nuts a couple of months back and I am germinating my own to use as root stock!
My plan is to then order scions from Burnt Ridge nursery in about two years and try my hand at grafting them myself.
For grafting chestnuts, Washington Chestnut Company has a great amount of info, which basically culminates to if you try to graft a cultivar from the one species (casteana sativa in this case) on to the same species of root stock, if your first fails then try another cultivar, and if that one fails try yet another cultivar, you will probably be successful by the third try. Since I'm in no rush, I can plant out the orchard and just keep trying to graft them until I'm successful and have the cultivars I want.
One thing I read which I now have discovered to be untrue is that "chestnuts have an extremely low germination rate."
Just like black walnuts, apparently :p
Well, so far at least half of my nuts have germinated, which means I will soon have A LOT of extra chestnut seedlings to deal with, since I will only need +-40 trees for the orchard area.
However, in doing further research, I discovered that chestnuts are also extremely useful trees for wood production in the form of coppice.
In Europe, chestnuts are trypically grown on north facing slopes (and oaks are grown on the south) and they can be cut roughly every 10 years for firewood, 20 years for fencing or every 50 years for timber. They then re sprout vigorously from the cut stump. There are individual European chestnut trees (called stools) that are thousands of years old after being repeatedly coppiced for many generations in this way, ever since the Romans brought chestnuts to Great Britain. They sprout very similarly to our native Bigleaf Maple that I'm sure you're familiar with.
So I plan to use these extra seedlings on part of my steep slope in order to make some good use out of the otherwise unusable site that is currently just alder scrub. They may fruit a bit but not much, but the deer will certainly appreciate anything that comes down!
Chestnuts also produce almost all heartwood very quickly, which is extremely rot resistant and can be used for long-term fencing without any further treatment! I encourage you to search for the UK government's information on Chestnut coppices, it was very informative!
Oh! One final very important thing I also learned - there is a general rule of thumb among chestnut orchardists. All site characteristics equal, any chestnut tree (including seedling trees!) will produce roughly the same amount of nuts by weight. The reason we have cultivars is primarily to ensure that that weight consists of fewer, larger nuts, because that is what has become desireable for the consumers (and it's easier for harvesting and processing.) However, if selling them is not a concern and you want the trees for their calories, a few seedling trees are just as able to serve your needs. (people also say that the samller nuts tend to be sweeter) I plan to run pigs through my orchard to clean up the leftover nuts some day, and I doubt those consumers will be too picky about the size of the nuts, and neither will the deer!
Good luck on choosing your chestnuts!