"Sill Life" WIP

Working on a print here. I plan on adding some wood grain to the green window frame and the shadow below the sill.

Regarding scale, I'm thinking 18" x 24", because I like the idea of it feeling like a real window when you hang it up. (Full thing attached.) Going even bigger would strengthen this effect, but I'm suspicious about what that might do to sales – as people don't usually have a ton of wall space for posters. What size would you like? You poster artists out there – what do you think?