Yes, indeed, wonderful model!
But sorry, I don't prefer photos or even colour drawings as reference. There is too much depending different things, as you told.
This model is very light grey. For example contrast between black (masts and funnel tops) and grey seems too big comparing for example photos in AOS. But because it is relatively small modell, light color is better, than too dark (scale-effect, mentioned before).
Otherwise, most of Dreadnought models (or similar) fe. shown in links earlier in this post, seems to be quite a bluish-dark grey, and that feels too dark, especially for original as-built color...
I hoped, if there is some original information about colors still available, as RN is so big navy, everything is perfectly standardised.
Br,
Ville H