Begonia, I think it has to do with our growing zone somewhat.
I have pollinated my brugs for 3 years with no sucess :(
I had hoped this year I had finally managed it but alas, no go.
I will keep on trying as long as I have 2 different types flowering at the same time.
Dr.Sues will set seed in a small pot by the way. I have noticed that some Brugmasia seem to set seed easier for me than others and some just need to be larger before one can set seed to them. All in all, it seems that the larger a Brug is...the easier it is to set seed to them. I do find that the versicolors, for me at least, seem to need to be a bit older than some of my other species before they will set seed. I have set seed on Dr.Sues x Ecuador pink though on its first bloom and was able to get a seedpod immediately from it that was pure versicolor in looks. Very fast growing Brugmansia versicolor hybrid or candida hybrid if one goes by the flower...and a very early bloomer to boot.