1) Should I prune all the vertical / 45 degree shoot?
2) Should I prune all the near horizontal shoot? Or just tie it to the stake to encourage it to grow horizontally?
3) Should I prune it to the main branch, or leave a few inches?
4) Should I do it now? Or wait till next spring?

Thanks

Do you want to keep it at three scaffolds? If you want to add more, you might be able to use the vertical shoot in the center or another that might start growing out of the top scaffold closer to the center by letting it grow out next summer and making a heading cut at the next desired level next winter to encourage new lateral growth for the next two scaffolds.

You can find alot of information online regarding pruning and shaping espaliers.

Mike

That is exactly what espalier is.

Mike

Why is because those top tiers will try to grow faster and shade out the lower branches and they'll never keep up if you go all horizontal everywhere.
After the lower branches get some growth you can then start letting top go to "keep up" with the lower and prune the vertical growth out.
This isn't from tried and true, this is from tried and failure. Give me a few years to see if it's tried and true but judging from the old ones (not really failures) vs the new the top will always want to outgrow the bottom and if it's allowed to start out like that the bottom kind of gives up.

Next year don't wait for some of that. Anything coming off the main trunk should be rubbed out as soon as you see it and it's just a bud.
Those really long ones can be nipped when you think they're getting long enough for your tastes, just pinch the end off.