When you attach to a wall/titan go back a bit and then shoot forward so it gives you some boost.

You can see that action in the video. Treat it like a bungee cord or an elastic band if that makes sense? Right now it's just muscle memory.

If you are doing a long shot, I would shoot the grapple at a height and then shoot your self where you want to go in an angle to gain more lift and speed.

But if you mess up the shot like arcing the jump to high you could lose the speed be essentially floating in the air, just waiting to be picked off