Some poor quality pics I just snapped with a phone of my espaliers.. the early pears flowering. They're about 5 yrs old now and the one apple I've shown has almost spread as far as I'll allow. It's about 7 feet between (aiming for 14 feet spread per tree)
Once they're all fully flowering and showing some leaf.. letalone later with fruit.. they look rather good.
Cordons , as you know, much the same process except closer together, angled and kept way more compact laterally. If tight for space then an easy way to get bags of variety.
I've got lots of space so have some 25 apples, 5 pears and 8 stone fruit along the fence as well as the original orchard and the ones !'ve scattered around (another 15 or so cherries/plums/pears)