Jim Coudal, on the perfect Martini:
First a note about substituting ingredients or tools. Don't. This method has been exhaustively tested and retested for excellence and the smallest variation can result in catastrophic and unintended consequences. See the "butterfly flaps its wings and causes hurricane" metaphor from Chaos Theory. There is room for personal preference and improvisation in many things. This is not one of them.
Obligatory reading. Gentlemen, you have your homework. Engage!