Quite simply, you wont be able to tell when your ready for real money by playing play money. I don't care how consistently you can win.
I was the same before I started real money play, I built up thousands of play money chips on party, thought I was hot shit, joined a real money game and got killed. Its that different.
The only way to do it is to jump in at the deep end and see what happens.
Join Royal Vegas Poker and you get free $10. They have $1 SnGs