The way I teach (vertical) trapeze mount is from a dead drop. It gives you more time and more control to catch the top. You just wrap the top, raise your hand in front of you and let the top (axis horizontal) fall just by gravity while unwrapping the string. When it is about to hit the floor (or the end of the string) you pull straight up. Grab the string with your non-throwing hand, close to the throwing hand, separate the hands about eight inches. Catch the top by letting it feed string from your hand.
The top will be spinning pretty slow but you'll be able to catch it. Try it. After you can catch it from a dead drop, start to give it a little impulse downward, and progress by increasing the force of the throw. You will notice that the top points in a different direction than with the dead drop (you should catch it facing out).
Good luck!
