I have a guide similar to yours. You should get duration decoy instead because if you do your decoy will shoot off two snipes. It is better in the long run. I can see why you'd wanna go with lower mana cost to have more mana available to harass with snipe in the early game.

Hi buddy,

I'm surprise with how you built your Nova and why this guide get so little vote. For basic skills, I use exactly the same with you but for Heroic tier, my favorite was Triple Tap since Fast Reload is a key for me to clear enemy team for a win late game due to its huge amount of damage. As you said, I found this way of building compensate very well shortage of Nova in lane/push/defence presence and constant dealing of damage.

Good work, keep going, man!

Hey. Great idea for Nova build. A bit limiting with the "Snipe master", because you tent to almost never use your snipe, just the decoy, but definitely thumbs up. I think that with this limitation, "Rewind" at lvl 20 is a must, so you can contribute enough to your team late game. It does miracles as I have explained in my guide on her.
I am really happy to see this new playstile emerging, and hopefully she will rise in the hero tears. Again great job.