No one seems to know how tall or buff Kaladin is, since his exact height is never mentioned and "fingers" is a completely arbitrary unit of measurement. There have been lots of questions asked about how Kaladin is so muscly if he lives off a slave diet. There have been lots of questions asked about how much Rosharan gravity and stormlight induced good health affects average height.
In this picture, I drew Shallan as 5'6"/168cm and Kaladin as 6'5"/196cm and he is slouching slightly. To anyone who ships Shalladin, how would this ship even work, logistically. She is eye level to his armpits and we all know Kaladin is lucky to bathe once a week...
Some other artwork to aid in your scientific research:
Kaladin at the Gym
Fanservice for Adolin