Have you ever raised any birds? I had one pair and was successful with them. They didn't produce any babies for me until they were four years old. Clutch of four eggs... all fertile. As big as cage as you can afford for them. I have photos somewhere of my nest boxes when I cleaned them up and sold the boxes. I don't recall the dimensions but could probably guess. Of course you know.... you can't count your chicks until they hatch. And... you have to be prepared to take care of them from day one if the parents prove to be unfit or unwilling to raise their own young. I might also mention... you should know the lineage on these crimsons you are interested in. They could be closely related as not many were brought into the US ( sixteen birds to be exact) in 1998 to a breeding consortium.