My J1 status expires on 30 June 2008. I want to apply for a H1B visa now already. If I choose to accept the H1B visa and start working in October, how much of a grace period do I have from when I choose to leave my J1 status? For example if I choose to leave my J1 in 30 June 2007, how many days grace do I have before I have to leave the country?