Last week, during my Fleet Officer/Rexlar experimentation, I found myself with exactly 33 points left in my build. Without thinking, I just plugged in a Bounty Hunter. It's a reflex for me at this point: I see a 33 point hole in my Imperial build, and the Bounty Hunter goes in there. There's probably other ways I could have gone: Howlrunner with Swarm Tactics and an Academy Pilot, Backstabber and Dark Curse/Black Squadron Pilot/Night Beast, etc, but I never even considered it.
Likewise, if I'm anywhere close to 12 points left in my build, I'll try to find ways to trim weight until I can get that Academy Pilot in there. I also recall SableGryphon once mentioning how if he sees 24 points left open in his list, he'll automatically run throw a Doomshuttle in there.
This made me curious if there are any other magic numbers that players have where players just have an automatic build that they'll throw in to fill the gap?