I own a 3R.
Weight of my 3R is 4 pounds, 7 ounces.
If I added the additional center pole, that would bring the weight up to about 5 pounds, I would guess. If you are going to use the tent in winter, you'd want the center pole, as it sags a lot under any sort of snowfall.
I've used my 3R in the winter, and don't really like it. In addition to sagging under snow load, the problem is the mesh at the front and rear of the tent. It's there to keep airflow going, and isn't a problem in summer.
However, I've found that in the winter, wind tends to blow a lot of snow through the mesh, and snow fills the tent. I've used the tent twice now in winter, and both times, I've had issues with lots of snow blowing into the tent and getting all over everything. There is no way to close off these mesh vents.
The 3R is my favorite big tent for 3 seasons, but I'm looking for something else for mountaineering.
There are a lot of Black Diamond Guiding Lights on close out right now. I may go with one of those.