Oh my gosh thank you for this! I could talk hcs forever and love hearing other people's. Here are a couple that always remain true in my head:
*Tall Craig my beloved. I think he's about 6'3 and always taller than Tweek. I don't hc Tweek as incredibly short, but definitely several inches shorter than Craig. Tweek I hc somewhere between 5'7-5'9.
*Craig is a hairy devil. Very manly. Takes after his mom lol. Love him with a hairy chest and it gets me every time a fic mentions Craig with body hair.
*I think Craig is a better student than Tweek. I think he's naturally smart and science/math oriented, doesn't always put the most effort into school but it comes pretty natural to him. Tweek on the other hand I think struggles more academically.
*For their future jobs, I love engineer Craig and drama teacher Tweek. I also really enjoy mechanic Craig and Tweek owning his own coffee shop/cafe.
*Tweek has a smart mouth and can be a brat sometimes, especially to his parents. He will sass them in front of Craig and Craig just sits there like 😳.
*I think the Tweaks are more financially well off than the Tuckers. IMO the coffee biz is pretty lucrative but I also hc Mrs. Tweak comes from a wealthy family. The Tweaks buy Tweek gifts and spend money on him instead of being present parents.
*I hc that Tweek wasn't a part of CATG until he and Craig started dating.
*Thomas isn't Craig's biological dad and he's several years older than Laura. Thomas and Laura met when Craig was very young though and Thomas adopted him when they got married so he's a Tucker. Craig barely knows his bio dad and considers Thomas his father. (I could def talk more about this one lol.)
*Idk if this is a hc or canon but Craig is always, always soft when it comes to Tweek. They can get into arguments but Craig is always the first to forgive or apologize. Tweek is more stubborn.

I feel like I've written too much lol but I am always up for talking headcanons if you want more! 😁😁