Yes you can do it. I have a row of tall spindle apples and every cultivar/rootstock combination is different. My trees are 3-4 feet apart depending on tree vigor. I would take a look at this tree spacing calculator and use it to get a feel for how spacing varies depending on vigor and other variables.
http://fruitadvisor.info/tfruit/clements/appletreespacing.htm
For scion vigor of more obscure cultivars look at this list.
Newer Geneva rootstocks are not listed in the calculator but you can use this chart to convert the newer rootstocks to older rootstocks with similar vigor for example G890 has similar vigor to M7.
https://ctl.cornell.edu/wp-content/uploads/plants/GENEVA-Apple-Rootstocks-Comparison-Chart.pdf