Kanku Dai for me from a Shotokan/Shorin perspective-good range of flinch response and receiving techniques, open and closed hand strikes to all levels, a couple of kicks, takedowns, wrist locks, an arm bar and a possible leg lock, several throws and escapes. 3 months would be a tall order though-what is happening in 3 months?
That said, there is so much overlap between kata in terms of application and principles (when real men only practiced one or two
) that real concentration on Bassai Dai or Enpi or even Jion would achieve something similar. Equally Gojushiho/Ueseishi or Unsu or Nijushiho/Niseishi might achieve good defence but teaching sometimes slightly different skills and principles.