Finished length needs to include take-up for rod.
Silk fabrics should always be interlined.
If a decorative rod is used, treatment does not return to the wall; there will be slight gap between drapery and wall allowing light to enter the room from the sides.
When using sheers and laces, valance is constructed at 3 times fullness.
Add at least 4" to face width and 2" to returns of any under-treatment, e.g. sheers, for proper clearance.
Rod recommended: Continental II or 1-3/8" pole.