We have done extensive research into poly lifestyles in the Bible. It all depends on whether you believe what the Bible teaches, or if you believe what the church teaches. There are also variations of how closely you believe the Bible to be God's Word.
Bottom line, for us, is that the Law outlines all the "rules" for having polygynous relationships. None of those were changed in the New Testament--in fact, the only admonitions against it are specifically given to church leaders, just as the Law specifically mandated that Levites not practice it.
We would be happy to share what we have discovered with any Christian who is interested. We're not here to proselytize. We'll share what we have learned with anyone--but our experience with certain groups of people have tended to be very negative when discussing our faith. So, if you want to know, drop us line. But don't drop us a line if you just want to argue and attack our faith.