I'm planning on making London Shades (with contrasting fabric for the inverted pleats) for my den and wanted to run some measurements and instructions by you guys before I start making them. I have 2 sets of two double hung windows, side by side, which measures 79 inches wide from outside of window moldings. The windows aren't recessed enough, so I'll make the shades as outside mount with a total width of 82 inches.

I'll have two swags (35" wide each) with 6" sides + the returns. Is 35" too wide? Do I need to make 3 swags instead?

How wide are the inverted pleats? The instructions I have call for 4" to make each pleat, which seems to be too small. I've seen another set of instructions for 12" allowances for each inverted pleat. I'm thinking 6" or 8"? I want the contrast fabric to be seen, so a larger width for the inverted pleats seems to be required.

Also, I'm planning on these London shades to be stationary as a valance only. My windows are 47" long from top of molding to sill. I'm planning on installing the mounting board a few inches above the molding. The problem is that the fabric I'm using is quite expensive and the vertical repeat is 25". So I'm thinking about cutting the fabric 50" long to save on wasting the fabric. They will be drawn up as high as they can go, so I'm thinking that it will look full enough at that length. Any thoughts on this?

Thanks so much for the help!