M.V.
It certainly feels awful to be micro-managed by others. Well-meaning control freaks seem to pop up everywhere, especially as mother in laws. I would recommend reading How to Hug A Porcupine by Dr. John Lewis Lund. It goes over everything you have requested information on. It will outline how to approach your mother in law appropriately too. There is a way to get results without insulting and torching the relationship from your side.
Until you find a copy though...you can begin with reinterpreting the comments your mother in law makes either in a more positive or a more direct way. For example, if she is talking to you through your baby (yes, I know, it makes you want to pop) you can say, "it sounds as though you are concerned with me bouncing my son on my lap, is that true?" The answer will be yes. "Why is it that you are concerned?" She will overflow with a reason, probably something about shaken baby syndrome or the nature and dynamics of their over-sized heads. It might be this or some other reason. If the reason sounds legitimate, you can thank her. If it sounds neurotic, you can restate what her reason is and have her check the soundness of her own comment as she hears it back. This usually is enough to diffuse the concern for the over-anxious control freak. You can reset the relationship back on positive by validating her somehow at this point. Something like, "I am so grateful that you love your grandson. It truly is a blessing with so many grandparents these days being too busy to care."
The irony of all this though is that, if you are perfectionistic or impatient in any way, your precious child could possibly be feeling this same way about you some day. In a couple years as his wings start to need stretching, he is going to seem about to knock them into everything. And you'll be able to foresee and predict each incident simply from having experience he lacks. However, if you prepare now, you can avoid breeding in him the very same resentment you feel for your mother in law right now.
Good luck to you and may many rich skills enter your life now that you are a mother, ones your mother in law might be equally eager to learn or know of, but isn't using.