That's right, Dan. I've seen the move but haven't tried Troy's alternate move. Anyhoo, with the striking vanish it'd have to be perfect Jay Sankey makes it look so easy in his "Leaving Home" routine with a key and string--come to think of it, he even botched the move in his explanation in his Best of Sankey DVD series--sorry Jay ;-)
Timing is alway everything.

Here's what I do:

I rotate the hand that holds the coin so that the palm points more toward the hand that holds the pen. This action catapults the coin with a minimum of movement. Make sure to have the coin slightly toward the thumb side of the palm. Looks like the hand flinches slightly from the strike.