Offensively, are they better to utilize one at a time or kind of in a swarming technique?
As a player who owns night owls and uses night owls as a
major air unit for a long time, I will tell you, basically if you're trying to
farm reso and doing many 35s and 30s, I will prefer using a swarm technique
(And the best things is: it is free repair! WhooHoo!) However ther's a lot of
times which you want to remove a specific target which is well defended (e.g. a
barrack full of SFs), I will prefer using a single night owl one at a time.
Hope my answer will help you through game.