For those that are wondering and I've done pretty well taking the #1 dps spot on world boss kills with 15+ other Demon Hunters that I'm beating out at 815 ilvl this is the way I play it currently.
Fel rush in, demon's bit a couple times with momentum buff, once momentum drops, VR out and Felblade back into Eyebeam w/ Blind Fury, then Fel Rush ani cancel for Annihilation Demonic spam. Pop Meta, and get momentum buff up anytime I'm spending fury instead of building fury. And this process continues until boss is dead. Making sure I always have momentum up to spend fury and don't worry about momentum too much while I'm building fury. For bosses where the hitbox is small, I really try to animation cancel a lot which I've gotten really good at. But for bosses where the hitbox is large and I can fel rush through them, I just don't worry about it and fel rush through to the other side and hit them from there to dump fury with momentum up. I have fallen completely in love with the playstyle ever since I started playing it and this was after I was scared to death reading about it, but once I got my hands on it, it plays awesomely. And at the end of the day if there's a fight where you can't move around, running prepared+felblade+nemesis will net you some pretty good dps still and you get to stay stacked (making sure you're comboing VR+felblade together)