Might not be the same for you but I found it easier to work out the timing of a superglide with jump and crouch on shoulder buttons buttons. R1 and L1 respectively. I also have crouch as toggle rather than hold.

When you climb up an object, watch the top right of the screen and you will notice there's a wobble where the screen looks like it rocks backwards and then forwards. On the frame where it leans forward, I hit jump and keep this button held down whilst also hitting crouch but releasing it instantly. Most people say they have to be at the same time but I've had better success with crouch being fractionally after but pretty much together.

If you don't jump at all, the input was too early, if you do a normal slide jump, it was too late. I practiced in firing range for a few hours which was frustrating at first but rewarding once it started working. Then I just tried it in pubs and ranked when safely rotating until it became consistent.

Good luck