If you look closely at my tri, you will notice that I didn't add the narrow strips of background to the edges of mine. I reasoned that with that strip sewn to matching background tris, my RS1 would look smaller, so I extended the lines of the design and did it that way. If you are intending to use coloured inbetween tris, then the 'frame' of the background will look good Just another thing to think about.
I have done several tris this way, after I realised what would happen with my tris matching my background.
I can't imagine that any of you will have problems with C3 or A5, being the hardened Janiacs that you are now. J8 has four little melons in the corners that will need applique, but even those should be relatively easy by now.
There is quite a bit of scope this week for those of you using three colours too.