This technique will get you killed. Please don’t do this. You just recommended slowing from 120 to 60, and if it gets really bad, slow to 30. Switching to the instruments at this point is waaaay too late. Now that you are in zero vis, you won’t see that the helicopter is spinning. Have you never been shown this in a simulator? Maybe check YouTube for that wedding flight that ended this way. If you feel the need to slow below 80-90, if you can still see, land, otherwise you need to commit to instruments and maintain speed. Slowing in IMC will cause you to lose control.