I'm going to make an educated guess (based on @hllulbh1 location) that this rav is from the most highly respected poskim in America. It's obvious why such a psak isn't publicized in writing or outside the community it's intended for.
Yes it was Rabbi Heinemann, and no, I was not in the meeting that this psak was verbally delivered. He had other rationales as well which will probably not be popular in this forum so I only mentioned the one which was specific to this City.
My broadest point is that there is daas Torah that supports much of the chasunahs, non mask wearing, lack of social distancing, etc. The rebbes of tens of thousands and rabbonim and roshei yeshiva of many more having the same medical and governmental information as others, have made it clear that these measures are not warranted. There is a current within these threads that insists that anyone that follows this daas Torah guidance and lead is irresponsible, doesn't give a hoot about other's lives, is selfish and you or your rabbis are more responsible and know better. Sure, there are lots of strong arguments (particularly by Lurker and shaulyaakov), but if the daas torah that many have been following to successfully lead a vigorous Torah life have gotten them this far in life, why abandon them now because of arguments, many of which IMO sound very much about kochi v'otztem yadi, "We did this and We did that and that as why We didn't get it". You can be commended for following your rabbinic guidance while those following other broad rabbinic guidance are not vilified for doing so.