Over the last week or so I've made a bit of progress shaping the ridge on the left side. There was lots of wood filler applied and grinding done to work in the shapes. Still lots to go. Once some parts were sort of done - like down in the lower left - I painted on some gesso to unify the colour so I could get a better sense of the shape. Then I thought I better unbag the right side and give some thought to shaping and balancing the entire layout as a unified whole. So, I think the next step will be to start filling in the major landmarks over the entire piece to make sure it balances out.