@ace, they dont need to blend
u just need to find a bg that looks REALISTIC to the focal....
all i see is blurry blobby type stuff (no offense meant) that just seems kinda, well, random i guess.....

i understand what your saying.
but look at ure timeshift sig in ure current sig space....
that is a good BG, because it seems REALISTIC to the focal, the colours and what not are similar, yes, but the focal still stands out and u can still see the fx.......so why not try using a bg in a similar way to the timeshift one? =]