I would be a bit careful about too strictly enforcing one turn each.
I have often found at meetings that the pattern of speaking on a motion is that I talked for a bit about a proposal representing the EC which is putting that proposal or most recently as a non-EC member putting a couple of personal proposals. Then someone asks a question or makes a statement that needs a response. Often it is along the lines of ‘Have you considered if X happens?’ or ‘This proposal could do Y’. Usually there is an answer along the lines of ‘Yes, we thought of that. That concern has been addressed by …’ or ‘We don’t think that will be a problem because…’. Sometimes discussion of a particular concern will go back and forth a couple of times between me and the person raising the concern before we move on to the next question/comment.
By the end, even though I really do try to not dominate discussion, I will often have spoken approximately once for each of everyone else’s turns. What is the alternative? To not respond to reasonable concerns for which there is a reasonable response?