Just built a stone house in Ytong. We had similar thoughts with large windows when designing the house. The result was 3 m in ceiling height, windows with module dimensions 11x17 and a sill height of 80 cm, meaning the windows align at 250 cm. We are very pleased and it looks proportional even in the smaller rooms that are 9 sqm. We went with 365mm stone, so the wall thickness is a bit thinner than what you had in mind...
