Throw tops are usually held with the tip up and thrown (if you're right handed) from right to left across your body. Here's a good YouTube how-to on the subject:
Rather than use a "button" at the end of the cord, you could use a looped cord (like with a yoyo), and tie it to your finger. But most players prefer the button, so the cord can be quickly re-used for tricks.
Most of the tops I've been making are larger than normal, usually starting with a block of wood about 3" x 4" to 4" x 6", and adding another 1/2" or so in length with the decorative laminations. Almost all production tops are smaller, running about 2" x 3".