Below are various designs for Window Valances from 1884, 1885 & 1888 These came from "The Furniture Gazette." Below are two tidbits about Valances, from these your characters might decide which one they prefer.
Here's a short excerpt from 'An Encyclopedia of Domestic Economy' ©1855 about Valances.
Betides tie rod on which tht curtain slides, there is generally a piece of the tame material with the curtain, called a valance, suspended before it, to conceal the rod, and likewise the soffit, or under side, of the architrave. This valance gives great richness and finish to the window; but when the rooms are low, they should not be deep, as they then hide much of the light: on the contrary, when the windows are very lofty, they are often useful in moderating the too great glare of light. Valances are contrived in a vast variety of modes, on which depends, in a great measure, the style of the window. Sometimes they are made in the form of festoons, and are then, by upholsterers, termed draperies i the festoon itself is called the swag, and the end that hangs down is termed the tail: see fig. 164. These are frequently ornamented with hinges, tassels, and cords, in various ways. This, which is the former French style, was introduced some years ago, as being much richer and more elegant than ours; at present it Js less used, and what are called piped valances are more generally put up; these harbour less dust, from the folds being perpendicular. Lately, massive brass rods and large rings have been much in fashion; also, rich gilt cornices over the valances.
Here's another tidbit from "The Art of Furnishings on Rational and Aesthetic Principles." ©1881
The simpler and more natural a valance is the better.
Our own opinion is that it is seldom needed. A light brass pole again answers the purpose as an ornamental curtain rod. Cornices necessitate valances, and frequently bring the window into excessive prominence, and detach it from the rest of the walls in a manner injurious to the general effect.
This next design comes from an 1888 copy of "The Furniture Gazette."