The key to iconography is patience.
The Seraphim, although seemingly simple, become complex with the successive colours in developing the feathers. Then mulitply that by 3 in this case..
There is still a long way to go. Once I get all three Seraphim to a similar stage, I can return to the icon of Christ to further devlope the colours before beginning the shading and highlighting.
I will need to gold leaf the haloes before I get too far along as I'll need to prepare the base (where you currently see the red basecoat on the halos. I need to do a bit of restoration on the paint immediately around the halo which can get scuffed a bit by the very fine sandpaper.
Note: I do the faces and hands last.