I like using Carapils because it lets me mash lower so that I get better efficiency but still have the body and heading. Maybe that makes it a crutch, but I can't get the same efficiencies at high temps that I can at lower ones.
Think of it like a stout, which typically finishes at a higher gravity than a pale ale. It won't necessarily be sweeter, but it will feel heavier in your mouth. (Edit: see post above mine...)
I personally like a light body in Pale Ales, and, if I were brewing this, at 4%, the idea (for me) would be lots of flavor in a light body so that you can drink a handful of them without being full/bloated/wasted.
That said, I'd use about half of that Carapils...other than that, looks awesome.