Hello fellow Noivern, nice color there XD
For Noivern I go with this
-Boomburst
-Dragon Pulse
-Air Slash
-anything (I gave my Noivern Flamethrower at first. Worst idea I ever had, now I gave him Hurricane for when I'm feeling lucky or playing on a terrain that help the Hurricane to always hit)
Now invest those EV on both it's speed and special attack. Air Slash can become Noivern main attack if you feel lucky it will flinch the opposing pokemkn, Hurricane can be used too if you're feeling lucky, and Dragon Pulse while quite useless, can be used for the STAB attack that have 100% accuracy, Boomburst however is going to be your answer on taking most of the Gym (I'm looking at the three of you, Serra, Ciel, Samson) go find a Silk Scarf and give it to Noivern, now watch it cripple your opponent or completely ohko them
EDIT: I'm pretty sure giving Noivern roost is not really a good idea, seeing how easily Noivern can be ohko, Super Fang/Tailwind can be a good alternate for Dragon Pulse, one is for halving any pokemon's health (which can be useful for the super boss) or giving your team enough speed boost to outspeed anything for 4 turn