I had a family tree quite a few years ago, it did well for me but not everything that happened was quite what was intended and I learned a thing or two.
It was a three-variety tree, shaped like a half-standard (chest height stem with three shoots coming out all equal size and labelled correctly). The varieties were George Cave (very early) Scarlet Pimpernel (even earlier) and Queen Cox (late).
It started fruiting at three years old, and already it was obvious that one of the stems, the Queen Cox was less vigorous that the two others. The rest of the tree carried on producing well, but the Queen Cox got more and more shaded out by the other two varieties. I tried to slow the others down by partly removing a strip of bark and cambium layer just below each of their shoots but they did not slow down. Instead a new shoot came out of the main stem nearby.
I let this new shoot grow, it was quite vigorous and it did not really look like a rootstock sucker. In three years the new shoot fruited and I identified it as a Tydeman's Early Worcester, which was a very good looking apple, second early, with an excellent flavour.
However the tree eventually became too large for the space it was planted into and I found that the Early Worcester does not take kindly to pruning, so after replacing the varieties that I liked (George Cave and Early Worcester) I regretfully took down the family tree.
I did not like the flavour of Scarlet Pimpernel.