Pumpkin itself adds very little flavor to the beer. Most pumpkin beers are made with the pumpkin pie spices in the boil and use low to medium attenuation yeast (residual malt sweetness). If you were going to use some of your rind, i'd add it to the boil at about 15 mins left. Taste a chunk of it first to make sure you won't be adding bitterness or astringency to your beer. If it tastes fine, add an ounce or two of chopped rind to your boil.
Beer so good, it's frightening.
2014: Seven Heavens Series One: Vilon, Mystic Melomel, Skeeter Pee.