wonderlandnice tutorial but let me just say the first part makes no sense.
I don't know what you're on about with jump+crouch like a soldier, thats just bad technique for both classes (unless you want a shorter controlled jump etc). also dunno how crouchjump is like ctap, its literally a normal jump the way you're supposed to do it. you press crouch first for safety. its textbook
it might be textbook for people experienced in jumping, but like lambda said the majority of people playing demoman crouch+jump at the same time, i´ve seen people with hundreds of hours invested in jumping that dont know this.
It all resumes to practice, but there´s good practice and there´s bad one, and i´m pretty sure this tutorial will help a lot to a good practice.
Its like spamming WASD on vertical airpogo, small tips and tricks that not everyone is aware of it