Great Stuff doesn't look ideal, since it's going to get a lot of sunlight on the outside, and Duct Seal doesn't say anything about whether it actually insulates. Also, the Duct Seal material safety ...
I have a number of ~3" holes in my plaster from where my walls were filled with insulation. (Why did they drill a 3" hole? I have no idea). Obviously I would like to fill these holes in, but they ...