While I haven't per-se, I have spent a little while looking at relative sizes of Sylvaneth gribblies and Grotesques/Wraithguard. From what I've found, the Revenants are a little small to scale directly with Wraithguard (although probably not enough to be accused of modelling for advantage).
Kurnoth Hunters are a much better fit size-wise
plus, they're awesome models