My wives don’t spend any time in the forums, like a lot of the women, so they won’t be responding to your question.
But what my first wife would answer is 3 years.
I would add that acceptance of the legitimacy of poly was just the first step in a very long process of growing in the knowledge/understanding of the culture. Acceptance does not equal elevated skill level. Also, as Keith said, growth on the patriarchal side of the table is a given for those who would go deeper into all that Yah has called us to understand.
All too often, people approach polygyny like getting a second car.
“I have decided to get a second, so I will just go to the second wife lot and pick out the one that suits my fancy.”
The first problem is that they are extremely rare.
The second problem is that very few of them will suit your fancy.
The third problem is that when you find one that suits your fancy, you almost certainly will not suit her fancy.
Don’t be like the many who marry in haste and repent at leisure.