Sorry, J1 qualifies as Visiting Scholar for the US and your purpose is to teach the US guys whatever you know. It does not qualify you to undergo training. I ran through this a couple of years ago and we found definitely no way to do that legally. My advice: during J1 qualify for a greencard and get a US citizenship later on. If you deny, think, because odds are high you regrat later not searching your way to US citizen ... just my5cents.