Quoted from Bublehead:
Some cardboard and tape and make a chute that diverts the coins over the coin detect switch and forget it, total cost $1.99. Nostalgia is one thing, but validating a coin for no good reason is a serious waste of cash. Coin mechs in my machines havent seen a quarter in decades. I know some players (like Rick Stetta for instance) who just keep a bowl of quarters near their machines because the coin drop is part of pinball... well, the cardboard and tape route gives you that for the least money, just not the least hassle.
Talk about being cheap
For only a few bucks more, I would buy the correct part to make it sound and work correctly without red green's help, personally.