Spent yesterday and today finishing up the mastery achievements for Nova Covert Ops.
Finally nailed the last achievement "Bringing Down The Big Guns", which required me to learn how to hold shift and Y, then spam left mouse click in succession, to get all my Battlecruisers to fire their Yamato Cannons on the Xanthos at the same time. The thing I had to take note of was to fire on the Exposed weakness of the Xanthos, which is basically the small pilot cockpit which is its head. It took me several reloads to realise this.
Another key factor to nailing this achievement was making use of the Battlecruiser's Tactical Jump ability, which warps the Battlecruiser to the target location without the need for map vision. Basically take a 2nd base fast, max gas asap, and mass Battlecruisers out of two reactored Starports. I got a fleet of 17 Battlecruisers before taking out the Xanthos at the end of its 2nd activation at around the 15 min mark.
1. Equip internalized tech module on BCs. Then you can churn out two from a single Starport, saving both gas for the starport and construction time.
2. Get +3 armor upgrades on your BCs. Barely costs you money and your BCs will not die like flies after the initial yamato barrage post warp.