Guo Cheng is 5'11" (180cm) and Zheng Fanxing is 5'9" (175cm) and in some shots Jingyi and Sizhui look around the same height but in a few others I saw earlier today they somehow look like they have a six inch (15cm) height difference or more.
This got me thinking about personal headcanons for height and I think I've settled on the following for their teen (immediately post-wwx-resurrection) and adult (5-10 years later) heights:
Lan Jingyi: 5'10" (177cm) as a teen, got a last major growth spurt that had him bedridden and begging Sizhui to take a rolling pin to the backs of his legs, has stretch marks that look like whipping scars, wound up 6'3" (191cm)
Ouyang Zizhen: 5'9" (175cm) as a teen, didn't have another growth spurt but did continue growing slowly and steadily, wound up 5'11" (180cm)
Jin Ling: 5'3" (160cm) as a teen (remember, immediately post-wwx-resurrection he's 3 years younger than the others), shot up like a weed, faster than Zizhen but not as bad as Jingyi, wound up a respectably average 5'8" (173cm) but retained all the energy of a half-feral rabid chihuahua from being the shortest once upon a time and the youngest forever
Lan Sizhui: 5'4" (163cm) as both a teen and an adult, did not continue growing at all, partially due to malnourishment as a young child, partially due to genetics, portable-sized and the others enjoy picking him up for absolutely no reason at all, seen that post about the 30yo and the helpful flight attendant? Sizhui
I know people ignore this every time I say it, but I do not care if this is contradicted by canon/word of god/what have you. These headcanons spark joy for me and I'm sticking by them ymmv
Teens Height Comparison
Adults Height Comparison











