So many windows would benefit from multiple treatments. You want light control, temperature moderation, sound insulation, and beauty. Throughout the day and the seasons your needs change; as many as three or four treatments on some windows would not be unrealistic, to achieve various combinations of sheer, semi-sheer, lined, or blackout layers.
Anyhow, my clients needed two layers of treatments on their kitchen windows, and there was no room for a curtain layer, so we did two shades. Underneath is a sheer linen relaxed roman shade, and on top a split roman, so they have multiple options for privacy and light control.
Each shade is on its own board, and there is a linen valance on the window-side of the board to disguise the mechanisms from view from the outside.