Here are a few rooms with the paintings in-situ, to give you an idea on size, and how they might look. When hanging any painting, always try to have good light on it, my preference is for mini spotlights aimed at the artworks.
30x40cm / 12x16" - This size is $390
30x40cm / 12x16" - This is the same size, also $390
40x50cm / 16x20" - This size is $590
60x76cm / 24x36" - This size is $1290
100x100cm / 40x40" - This size is $2900