I have red bush cherries (nanking I think?)here in Ok. I brought about 30 mail order from ind. or ohio? there pretty cheap so you won't be out much if they don't do well.

They do very well in sandy soil. I have a clay self on the other side of my yard with some planted on that side. The clay in my yard is very solid (hard)and the cherries struggle on that side. I also have tall trees and the C. bushes on the sandy side flourish with about 40% sun light a day. I prune them back to about 6 foot every two years. they make good P. block in the spring and summer and really produce alot of sweet little cherries if the frost don't burn them when blosseming.

I guess it depends on how hard you clay soil is? I would dig the big hole and add some sand for drainage I think they will do OK. I planted them about 1 to 2 foot apart and the red ones produce new plants the next year off the pit seeds that dropped and left in the soil. the purple ones are very tart and reproduce through the roots. I don't recommed the purple unless you like a very tart cherry. IMO they are too tart to eat. I wish I had some of your hickory trees, all I got native are black jack oaks.