Please remember that everything is on hold due to a family emergency.
As for dual pol in GR3, 1st ,the local radar has to have been updated which will take nearly 2 more years before all NWS radars are updated. Once GR3 v2 is released, you will be able to view dual pol data IF the radar has been updated. As for test or beta versions, there is not one available through the forums. Only a select few have been given that privilege.