[The Chief (tm)]

I guess I'm gonna try to "convince you [you're] wrong" with this one! But only because it would be *very* easy to kinda "make sure" you, in fact, DON'T like it:

Have you tried to see what it would look like if you DID blacken the "thin strips" at the end of the blade spoiler? (By which I take it to mean the little section between each side of the spoiler and the trunk cut-out line.) Easy, because you could just cut out a black piece of paper and rest it on there, to take a look.

I feel like I could also see having the paper taper to a point at the trunklid, i.e., it fills the width at the front of the spoiler (closest to the window), then tapers inwards until it is ends at the rear of it, right at the rear-most end of the horizontal portion. In fact, this would probably look "less unfinished" than what's from paragraph above.

So, maybe, cut out some paper that covers the entire part first, and if you don't like it, then cut those pieces further in a diagonal line and see if it looks better.

Otherwise, from among the two choices in photo #3, I think I go with the first one, the "one big stripe" move.

Keep us posted!