A couple of thoughts and observations I have been meaning to mention. For those of you who are intending to make your outer tris in the same fabric as your backgrounds, you might want to consider slightly altering some of your pieced tris. For instance, I didn't do that for RS11, as it hadn't occurred to me, so I dutifully sewed on the very narrow strips of background along each long edge. When I realised how sillly this was, considering that narrow strip was going to all but disappear against my plain tris, I stopped doing it. So with BR2, I just extended the central areas of tri to make the tri big enough to trim down with the ruler, without adding on the narrow border. The same went for RS1, again I extended all the coloured and background sections and avoided the narrow outer strips. There may have been one or two others too, but these are the ones I can remember offhand.
My other observation, now that I have assembled my borders, (I only have one on, so far,) is for those of you intending to QAYG. When you choose a quilting design for the outer, plain tris, make sure that it leaves you a half inch unquilted on both long sides of the tri. It will make it much easier to assemble the border, and you will be able to quilt right to the edge of the pieced tris this way.