DavyC is completely incorrect lol. Ctap rocket jumps with the 1 tick bind still require timing, and the other binds are just worse than manual ctaps. The timing to ctap is to tap crouch and then jump before you are fully uncrouched. This isn't very hard, but the shorter you tap crouch for, the shorter the window you have to jump. Doing manual ctaps consistently is extremely easy, but doing them in 1 tick manually is very hard.
To do a ctap rocket jump you have to time your shooting and jumping. For a perfect pencil, you have to jump 1 tick after you shoot. This is the same with or without the 1 tick bind, and the 1 tick bind doesn't affect this timing. Doing a perfect ctap rj has the same timing with or without the bind. You get nonperfect ctaps if you fuck up this timing. If you jump too late, you get a crouch jump or no jump at all. If you jump too early, you get a worse ctap. You also have to vary the timing depending on the angle of your jump. Shallower rocket jumps require you to jump later (or shoot earlier).
The reason most binds are bad is because they fire on the same tick that you jump. This gives you consistent ctap rocket jumps that are imperfect. They also don't vary your timing depending on the angle of your jump, meaning they give you even worse jumps if you are trying to go more horizontal instead of vertical.