I see two problems: One is the bitterness might be a bit low for a relatively big beer with lots of crystal malt. Of course, if your goal is a relatively sweet beer, disregard that statement. Two is adding orange zest at 15 minutes: The primary result of this will be an increase in bitterness steeped from the zest with no increase in orange flavor. It'll all boil away!
To keep the "Triple" in your recipe (which I may crib), maybe zest three different types of orange like tangerine, sweet orange and bitter orange?