If I knew when I'm supposed to use {-mey} on {gher'ID} and when not, I'd be happier.

Not as happy as I'd be, if I won a million euros, but I'd be slightly happier than I'm now.

I mean, what the ghe''or is happening with this word ?

Is it inherently plural ? Can we pluralize it ? Why are some of its' meanings singular and some plural ?

My guess is that the word can be applied in the singular to the outcome of a singular process, even if that consists of multiple components, the "results." One process, one gher'ID. If you performed multiple processes whose outcomes were not linked into a whole, they would be gher'IDmey.

Suppose you throw a ball into the air and want to see what happens. Its falling to the ground is the gher'ID. If you perform the experiment multiple times, each result is a gher'ID. The collection of all of them would be gher'IDmey. But if you combine all your separate gher'ID into a single conclusion, that is a singular gher'ID too, albeit a different one that has all the little gher'ID as its component parts.

This is just my guess.

-- 
SuStel
http://trimboli.name