Based on my experience, OVERT is better than COVERT. Yes, it is a "shift in mindset" and takes courage. You can try it first at some random, not at your regular company. Better first tell them jokingly that you are an occasional stutterer. So they will be prepared. Once you come out of the closet, carry on and never return to COVERT mode. If you feel a block, take a deep breath and say something like: "Sorry guys, I've had a bad night, so my speech will not be fluent, though it has never been ( with a grin!!! ). Pick the words that will be easy for you to start. Good luck. And what I always recommend is to try acting. Imagine yourself Schwarzenegger or Stallone, and you will find it much easier. Like a stuttering character Wabash in the movie "Shakespeare in love". Don't be afraid of bad reaction. It's mostly your imagination. Use it as a comic effect to your advantage, And remember, If I and many more did it, you can do it too. That's all for now. Good luck.