Again, familiarize yourself with a hotaru delay jump timing, and use that for all situations. You can adjust height with delayed j2C and delayed 5C, which are better suited for the purpose. Hit confirming on jump delay is going to be significantly more difficult.
Furthermore, you will have to do that for every character, as most have different aerial hitbox. I find that hazama, Litchi, and Arakune to be most variable, with Carl and Bang following them.
Also, keep in mind that in a real match, 5CX2 isn't the most important piece. You only get about 300 more dmg for the additional link, so never surrender a combo if you mess up that piece of the combo. There is no reason to give up free damage, but there is also no reason to not finish the combo. When in doubt, always skip the link.
Finally, the hardest part about the combo is actually when your opponent is at variable heights (in relation to you). The only thing you can do here is just learn through match experience.