For my wearable muslin I used 3 Mossimo for Target tissue-weight t-shirts (size XXL), on sale.
Making the unwearable muslin:
At this point I made an “overall shape” mock-up by cutting and pinning (time after time) one of DH’s oversized white t-shirts. Eventually I arrived at the muslin pieces as shown in the slideshow. Next, I added a wedge to the upper front for the cowl-neck effect. Lastly, I freehanded the stitch lines to mimic as close as possible the original design. Then I transferred the muslin to paper and trued the topstitching lines so the back and front matched.
From there, I cut out the separate pattern pieces.
This slideshow illustrates the process:
Seams are first serged, then pressed tone side, then topstitched with a coverstitch machine (the parallel lines remain on the wrong side).
The lines that are only topstitched I first interfaced with 3/8” bias fine-knit fusible.
The neckline is faced and understitched.
Hem is folded under and topstitched.
These are photos of the WS and RS of the stitching
To do for the contest entry: I do have some tweaking to do, reposition some lines and rethink construction, but really, the style is so loose that I do not foresee any major changes. With other words, the fit was the easier part with this top. Now, I am impatiently waiting for my samples and then fabric to arrive!