Many cases for unpaid overtime are settled before trial with the agreement that it will be kept confidential. You may joepardize any chance of settlement if you publicize the case.
Don't do anything before consulting with your attorney. Based upon the facts you present, a class action lawsuit in federal court could be commenced under federal law( The Fair Labor Standards Act) and state law.
The responses provided to your questions are not legal advice, do not create any attorney client relationship, and are provided for informational purposes only.
In terms of a discrimination as opposed to wage and hour case, the question would be whether he maintained such policies only for employees of Hispanic national origin. I hope your case includes the New York Labor Law as well as the federal, because the State law allows more years of back pay. I would not attempt to reach his customers. He'll just pass it off as a letter from a disgruntled employee, and you may be liable for interfering with his business relationships. (Admitted in CT and NY)
The above does not constitute legal advice in any specific situation, and is provided for informational and discussion purposes only.