Yours looks sweet. Good job. I'm not a great painter and I had a heck of a time painting mine. The worst part was the letters themselves not being perfectly formed on the blanket.
Yeah, those letters were a DOG to paint. I used Testors acrylic paint like you use for models, and it soaked into the blanket like a water on a sponge. It was tough keeping enough paint on my brush to get it done. I tried to tape around the letters, but the tape pulled off part of the blanket when I would go to remove it - so I just freehanded it.
I really don't think you have anything to worry about with the flaps, most of the splash on the engine bay comes from underneath. Just pull your blanket down a bit and fold the slats back and under the blanket. That way they are not cut off and you can move them back if needed (read - warranty issues).