Grytviken church- work in progress

I've been working on a full imperial-sized (22x30") painting of Grytviken church, based on the sketch  I put on a previous blog post. To scale up the sketch, the full-sized version is around 1.8/1.9 times the sketch size. As I don't possess a pantograph, and the maths were too much for me, I opted for the simpler solution of just scaling it up x2. Whilst this doesn't sound much different from the 1.8/1.9 scaling, I was worried that the church might appear too large in the finished painting. The aim in the sketch was to show the church dwarfed by the surrounding landscape.
I did a cartoon on cartridge paper rather than drawing straight on to the arches 300gm watercolour paper, as I wanted to get the drawing of the church just right. Seeing it from a sitting position, and slightly off to one side, there is already a degree of distortion which needs careful treatment. After a bit of trial and error, I was reasonably satisfied with the proportions:

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I'm part way through the finished painting, having started with the sky (not too happy), then the distant mountain (better) and the middle distance rocks behind the church. With a bit of ultramarine for shadow, it is now starting to take shape.