First, the 9 raw files were corrected using Camera Raw – a small amount of colour warming, and some lens correction for verticals.
Then the 9 files were opened as layers in Photoshop. The darkest image was masked, so only the windows were visible. Then two of the lighter layers, with better exposure of the interior, were moved. In the end, these were the only three layers used. The lightest layer was changed to low opacity, and the image saved in two versions – with the lightest layer and without. There is some masking adjustment still needed and I should also lighten the darkest veranda areas to improve the image.
The first screen shot is with just 2 layers used. The second is with the lightest layer added with transparency added to this layer. The other two images are the resulting images.