The deeper the cascade, the more difficult it is to keep growth balanced. When I get home to my laptop, I'll share photos of mine.
A full cascade the decending branch extends below the foot of the pot. The semi-cascade the branch terminates between the rim and the foot of the pot. Full Cascades are a pain, as they always have to be at the edge of a shelf, so the decending branch doesn't get broken.
To keep foliage balanced, the upper parts of the cascade will sometimes need pruning 3 times more often than the lowest part of the tree.
To start a cascade, first plant the trunk at an angle. A trunk that is perfectly vertical, looks wrong on a cascade. I'd angle the trunk to either 60 degrees or even down to 30 degrees off horizontal. The younger the tree when you change the angle of the trunk the better. This allows you to develop the root flare, or butress at the base of the trunk (nebari). You can work out the decending branch later.
This is just the start.