The pecking order doesn't seem to come into play for my puffers because they have completely different tastes. Pudge-- the decent-sized one-- will gladly let Matilda eat all the frozen food and any live shrimp. But he'll fight her out of the way to get a cricket or a snail. Although maybe their individual tastes are somehow affecting their growth patterns.
She may just be a small subspecies. *shrug*
This is off-topic, but you may be able to answer another question I have... I know that GSPs don't breed in captivity, but do you know ANYTHING about the way they breed? Mine seem to flirt routinely. They often bump sides against each other in a manner that almost resembles a spawning embrace. They even "cuddle" together when they go to sleep, which-- by my understanding-- is extremely unusual since they're a cold-blooded, nonsocial species.
You seem to have a lot of experience with all sorts of puffers, so maybe you've witnessed GSP behavior enough to have some clue of what's going on. Could they be working on making some babies? (Btw, I've only guessed their sexes. I know that there's no reliable way to sex them.)
Thanks so much for your help!