which RG necks are we talking about exactly?

... RG7xx necks are pretty thin, flat and fairly consistent from one axe to the other.
... RG5xx necks varied depending on period; my 92 550 feels "beefier" than my 760 and one of my friend's 770DX ('91). I've played a couple different 570's (early 90s) and they felt flatter, almost like an RG7xx neck.
... modern RG Prestige necks vary as well but they're consistent across the board; the 3120's i've played before felt like a very smooth and stable RG7xx neck IMO.
That's my take on RG necks
Reg