I've managed to cut the dress out. I've been worried about visible-entire-panties (never mind VPL), but I've managed to make the dress 4 layers thick. I got 3 copies of every pattern piece out of the under-6m of light grey stuff, plus a single layer of the stripes. Of the 4m of stripes I bought, I probably have over 1m left.
The fabric turns out to be 50p/m of pure hell to sew. The light grey stuff I'm using as lining turns out to be quite stretchy and probably a knit, while the stripy stuff stretches like crazy on the bias. Both fabrics are super drapey and slide all over the place. Their only saving grace (apart from the price) is that neither fabric frays too much.
I've sewn all the bodice darts and the centre back and shoulder seams. I then used the magic of inkscape to trace around the edge of the ruffles in a photo of the dress I'm copying, and compared the length of the ruffle-y edge to the length of the neckline. It turns out the ruffles are probably 1:5 or 1:6 (wowzers), so I've gone for the 1:5 option. I should probably do a tutorial on how to make these ruffles.
After much ruffle assembly, I've attached them to the neckline and sewn in the lining around the neckline. My next plan is to top-stitch the lining down around the neck, but hiding the top-stitching under the ruffle. I hope this will stop the neck gaping open, but who knows if it will work as the ruffles are so heavy. I added a fusible interfacing strip around the neck too, but I'm not sure if it's enough to stop this dratted fabric stretching out of shape here too.
Next I'm planning to install the cap sleeves and attach the armhole lining as per this timely tutorial posted on Elegance & Elephants yesterday, just as I was considering how to do it! Then it's french-seam time on 4 layers of skirts *yawn* and the hell of an invisible zipper into 2 layers of this &^"£* fabric. At least the edge finishes are quick with the overlocker rolled hem feature.
ARGHHHH I don't even know if this dress is going to be wearable and it's taking forever! Give me some nice non-stretchy cotton any day...