What is the diminutive of κῆτος?

Question

A classic diminutive suffix in Ancient Greek is -ίδιον, which forms a neuter second noun.

But what happens when this is applied to a noun with a vowel in the stem? For a concrete example, if I wanted to talk about a "little sea monster" (using the noun κητε-), would that be a κητίδιον, a κητείδιον, or something else entirely?

(I'm most curious about Attic, with its patterns of vowel contraction, but answers for other dialects would be interesting as well!)

Answer 1

The adjective κήτειος for kēte(s)-ios, with the usual contraction of ε + ι > ει suggests that we should expect *κητείδιον as well.

Answer 2

It looks like Greek speakers weren't too sure either. I did a very cursory search through words in -ίδιον on Perseus and found one example of each type:

τειχίδιον < τεῖχος "wall"

ἑλκείδιον < ἕλκος "wound"

Both these words are rare and my search was far from thorough, so I'm sure there's more evidence to be found.