Option 3: Velcro attached to the face of casing.
Determine where your velcro will be on the top casing face.
No Sill - Measure the window and casing from the top of the Velcro to the bottom edge -
this is your Window Height.
You then add 1/4" - this is your final Shade Height.
With Sill - Measure the window and casing from the top of the Velcro to top of the window sill -
this is your Window Height. You then add 1" - this is your final Shade Height.