It's slow going over here in Green Acres, partially due to laziness, and partially due to the omg-howmuchyardage!?-for-trims that comes along with many bustle projects.

My original plan for the trimmeries on my underskirt is as follows:

Figuring out how much yardage I needed for each type of trim
I've done away with the flutes nearest the hem because they ended up not showing under the deep pleats.  The ruffle in the middle will become a ruched band instead of a free ruffle.  Otherwise, it's all-systems go.  I cut out all the strips of self fabric needed, and have been stitching them together, ironing in hems, and beginning the tedious task of pleating, fluting, and ruching.

Before I could apply these trims, though, I had to mostly finish the skirt, and mark it for trim placement.  I decided to do this mostly flat (although my waistband has been attached - you could do it completely flat, though, and do the darts and gathers last), measuring up from the bound hem, and marking each placement line in chalk.

Lines marked in chalk
I discovered an issue with the train on the skirt, once the whole thing was together - the back did not want to train nicely.  The back panel on the pattern is a straight rectangle, with the waist tightly gathered into the waistband.  I thought I could train it by cutting it longer, with the side gores adjusted to meet the additional length at back, but the whole thing needed more of an arced shape to work, so I applied a godet that will be covered in trim.  The godet could have been even larger for more spread.  Next time I will know to cut the shape of the hem on these narrow skirts in a more circular fashion.

Other deets - the whole skirt is lined in lightweight cotton muslin, with a foot of hair canvas at the hem for stability and weight.  It weighs more-than-a-little, but the paper-thin Dupioni needed some structure beneath it, particularly to keep it from stressing too much at the top and hanging funny from the weight of the trims below.

One last bit before I run off to pleat 102 inches of flounce - the flutes!  So...after my test piece, I went for the whole, huge, 190 inches of fluted trim.  I discovered that the practice does take, well, practice - there are many factors to consider, such as how wet the fabric is, and how hot the plate and iron are.  I initially used vinegar to set the pleats, but had better luck with spray starch.  The next time I will use quite a lot more starch - it didn't hurt the silk at all, thank goodness.  The biggest revelation, though, was the very last action - run a gathering stitch along the top edge of the flutes.  It transforms them from "meh" to "holy-wow-flutes!" and keeps them in place when you go to sew them onto your garment.  The gathering stitch is the key.

Fluted trim, with the gathering stitch run along the top edge.