I just received my Supermid last week, I have not gotten the chance to use if yet, but think with any more than 3 persons WITH gear you "might" have issues with rain over the door coming in and out? With the angle of the walls there is not as much room at your head and feet as you would think for a shelter that's 9' X 9' Still a great shelter though, that I'm looking forward to using this winter, at least a few times anyway? I guess you might be able to place 3 persons with (1) person at each side and the 3rd at the back wall with your gear down the middle, but away from the door?
I should mention I had a Golite Hex3, and for 2, there was never any problems with rain over the door coming in and out. The Hex3 was great for 2 but not really big enough for 3, IMHO anyway.
Probably the best way to deal with rain in a group is for someone to carry a 10x10 sil tarp and store all your gear under this and hang-out and cook under it too. I don't know how many times we all had to crawl into our shelters early because of rain, and the tent or shelter was your only means of escaping the rain, and getting some relief from it.