Took me 5-6 hours total across two days to grind the engrams in Skywatch. Using Ogre, heroic events, and basically killing everything I saw, trying to pick up every ammo brick I could in case that affects drop rates, etc. Twenty minutes to get the 100% kills. Makes no sense to have two objectives for the same quest step be so dramatically different in terms of time sink. This smacks of not being well thought out in the slightest. Grinding mobs in a starter zone for hours on end is not fun, Bungie. It's a chore. You know better, which makes it disappointing you chose this route.