Great idea from Miss Mustard Seed for making a template when hanging curtain rods. I would mark both sides and check to be sure they& level before drilling though. Not all windows are perfectly level - especially in older homes.
Spray paint electrical conduit and you have curtain rods - there is an idea for easy pinch pleat drapes on this website too. I use a copper plumbing pipe between brackets to hang lots of plants on the back porch.