Automobile 2 - Odds and Ends pictures by kach22i - Photobucket
I'm saying that following the template is best for aero, always.
In addition (open to debate - just my two cents), going with a 10, 20, or even 30 degree angle may be even more effective than following the template. However you invite uplift.
My point of this being a FWD car, and if not adding down-force to the front, you would not want to add or subtract very much force from the rear.
I think the original image (not my side view) is at a slightly up angle (see yellow line above) than template perfect. However the tiny amount of down-force here may in fact be equal to any chin spoiler and or splitter down-force we are not seeing from this rear angle photo.