The jump button appears to be unrelated to the height of the jump. Beat (the first character) appears to have two jumps: short and huge backflip. Are there other kinds of jumps or is this dichotomy accurate?
What determines the height of the jump? Is it related to when Beat says "Yeah!" or "Nice!"? Is it related to the score or current combo? Is it related to the length of time grinding or boosting before jumping? Does this change between characters? Not knowing this complicates my path-planning.
Specifically, when attempting a large combo in the tutorial my second or third short jump button presses on the large rail result in a Method Back Flip or Flying Kite. How can I predict when this will happen?