How about some more info.? Are the trees for your back yard or a hunting property? Do you already have soft mass available on the property? Are the trees for you or wildlife? Generally the bigger the better, people recommend circling the trees with brush to prevent overbrowsing and protect the trunk with a plastic tube. Here's a link with more info
http://aggie-horticulture.tamu.edu/extension/homefruit/apple/apple.html