Hey Drew,
I just headed mine back, and am hopeful a 4th ‘main scaffold’ will form this year, based on a green bud.
With KGB… when heading back in the early years, to form secondary/tertiary branching, does it make sense to remove buds on the bottom of the branch (when not immediately next to the heading cut)? I can’t imagine those will be kept, as other pruning forms also have these downward facing branches removed…
. Removing the buds you mention is fine. Up to you how you want it to grow.
I don’t mind the downward growth on older scaffolds. I often prune to them to keep scaffold more horizontal.
I have a White Gold that is entering its fourth year on a Krymsk 6 root stock. I am attempting to train it to the KGB system and it seems to be working well so far. At least for a first attempt for an old dog. It has produced a lot of fruit buds and hopefully the birds will leave a few for me. My soil is a clay soil, fertile and in full sun with fair drainage. The charts seem to compare the Krymsk 6 close to the Gisela 5 which might be an option for you.
Here are a few pictures of my tree. The tree was summer pruned and I plan on pruning it again when it blooms to bring the height down some mostly.
