For commercial plantings of apple trees on dwarf rootstocks typically spacing is 3-4 feet between trees and 11-13 feet between rows. In practice, soil type, irrigation, scion vigor, rootstock, target tree height and pruning system all play a role in establishing spacing distances. I have linked a calculator below that allows you to calculate reasonable spacing distances. Also heirlooms often have as much or more vigor than commercial varieties- you really need to know the vigor of the variety in question to estimate the spacing needed.
http://fruitadvisor.info/tfruit/clements/appletreespacing.htm
This list estimates apple scion vigor.
Cherries require more space.
You’re wanting to basically have the rows be 4 foot apart which is about a third of the distance that is recommended. And a commercial apple orchard has no shading from surrounding trees and buildings which is almost a given in a backyard orchard.
Also your profile lists you in zone 8b. What state are you in? 3 in 1 hole planting work in arid regions out West like parts of California where the disease and insect pressure is extremely low. 3 in 1 hole plantings in the East are going to have disease and pest issues… you want more space for trees.
With the available space you want to put in fewer trees.