First, we tried the UFO system and I can’t say it is everything people claim. That said, you will need a cross wire every two-three feet up to your desired tree height, which will be based on the rootstock you choose. A good rule of thumb for most cherry trellis distance is 40′ between poles, but a “V” shape should be closer than on an upright UFO as a “V” will put more weight on the wires to support the crop. Clean buds off the bottom side once they start pushing (just slide your hand along the bottom side to thin them off) so all your growth is on top. Make sure the tip of the tree is always pointing up so that growth doesn’t move down towards the roots. Take out any upright that is too big (the same size as the bottom cordon) in season as a “stop” cut, or any that are too small in the winter to stimulate regrowth as a “go” cut. Use Promalin on any blank spots. A good resource would be Mark Hanrahan, he has some stuff about UFO online, especially his experience of what not to do.