My horticulturalist friend explained this to me quite fast so ill try to asnwer as best i can.
From my understanding you simply hijack the whole rootsystem of a Tree with a clojne. This will result in the plant itself growing A LOT faster sice it already has a developed root system. It can put all its focus into growing. When they do this in the apple industry im told they kind of get poles sticking up from the soil packed with apples (they also train the clones ofc) wich means they will get more apples per m2/sq.ft of growing. i dont think the grafted clone will take any growing properties (noding spacing etc) from the original plant which the root stock belongs to, but rather the rootsystem will still have the same properties. In the end this is a technique used for outdoor growing so i dont really know the extense of how it works indoors in pots. But hijacking in example a 6gallon pot of roots with a cutting well.. u can see the benefit right? i still hane not been able to experiment so much withthis techniques indoor yet since i have a rather limmited growing area.
Ill talk to my friend again when i get a chance since she has a lot more experience than me + she is a horticulturalist so she is another level than me when it comes to understanding anything regarding plants. I'll get back to you with more details after i talk to her.