I use this height range as my basic guide for the average of each caste. The lower a land troll is on the spectrum, the more likely they are to be shorter. Psionics also play a role in height/body type, because energy going towards your brain powers means less energy being spent on growing, so low bloods have a more wild range of heights, although the average still falls into the “short” range.
The higher you go on the spectrum, the taller your average height tends to get, so there’s this intrinsic bias that taller trolls are higher on the spectrum, regardless of where they actually are. If study participants are shown two yellowbloods of exactly the same hue, but one is four inches taller, the results of the study will show that the taller troll gets ranked higher on the spectrum the majority of the time, even if the trolls participating aren’t aware that they have that bias!
Seadwellers tend to have a muuuch larger average range of height just depending on the part of the ocean they come from, the type of fish/sea creature they take after, ect ect. But if you’re a land troll, you don’t need height as a quick cheatsheet to guess if they’re higher on the spectrum than you because they’re going to have fins or gills and probably be slightly uncanny valley to you as well.
And if you’re a seadweller, it’s probably some sort of sport among the nobility to sit there and nitpick whose blood is higher than whose, I don’t know, that seems like a fun game that would result in bloodshed and probably perfect for the kids of a ruling class in a warmongering society.