I think the problem of the "hyper middle ground" is that what constitutes a "hyper" dick in TiTS is sort of all over the place. If we're going by real penis standards (which I know we aren't), 10" is a
huge dick. Like top few percentile big. If we go by the unofficial "8-inch porn standard" that's been discussed before and seems to be supported by the various in-game dick measurements, 10" is
still 25% bigger than average.
I personally would consider any IRL dick over 10" to be "hyper." 10" is twice as big as average, and going up to a foot long dick is insane. In a space porn fantasy, 16" seems like a good cutoff for declaring something "hyper," as it is also twice as big as the 8" "average." I know there's plenty of size kings and queens out there, but seriously, a 16" cock is fucking ridiculous. I don't think there should be any "big dick" scenes other than "ultra hyper" scenes (something like my as-of-yet-unimplemented female naleen tailjob, for example) that aren't accessible by a character with a 16" dick. And then, most characters/encounters should probably be able to accommodate up to 16" in at least one way. Even Aislinn, who is supposed to be very small and will have among the strictest vaginal limitations in the game, can take up to 16" in her ass.
Granted, this wouldn't really affect the OP because using dick length as capacity shorthand immediately implies the default thickness ratio. Which has obviously been surpassed several times over in this instance.