First, I confirmed with Sarai, the pattern's designer, that the back pieces should not wrap all the way around to your side seams. They should definitely cover your back darts, and then end about 1-2" away from your side seam. The fit in a wrap dress is more flexible than other garments, so don't fret too much about this number. I did let my own side seams back out to give me a bit more wrap.
Next, let's talk about darts.
Your darts should end about 1" away from the apex (or fullest point) of the bust. The darts on this pattern are a little long on some people, me included. No worries! It's easy to shorten a dart.
First, make a mark 1" (or however long you need to shorten) from the tip of the dart. My new point is marked in silver Sharpie below.
Next on the dart agenda: moving darts up or down. Your bust darts should be level with the apex of your bust, no higher or lower. The darts on this pattern seem to be a bit high for some. The easiest way to lower a dart is to cut it out and move it down as far as you need (have some new pattern paper taped underneath). Re-draw your side seam line. (You can see this method in action in the book Fit for Real People, but it's really as easy as it sounds.)
And lastly on the subject of darts, re-shaping a dart for a more flattering bust look. Some of you may be noticing a bit of bagginess under the bust. You can re-shape the dart to get a more stream-lined look. First, draw a line about 1-1/2" down from the tip of the dart (this measurement may be shorter or longer for your personal fit), making it perpendicular to the dart's center line. My new marks are in silver again.
Finally, let's talk about transferring muslin alterations to your paper pattern. After you've pinched out whatever excess ease you have on your muslin, take your muslin off but keep the pins in. Mark the "humps and gullies" (as Sharon would say) on the pins, as below.
Next, you can deal with your tucks. You can't just take a tuck out of a pattern because it changes the position of the neckline and shoulder. Here, I've taken the tucks out of the original pattern.
You want to use the original shoulder position, but the lowered height of the piece. Trace your new lines and slash through your old ones so you don't get confused.
Always have a bunch of different colored pens and pencils for this purpose! Slash through any bad lines, and draw little circles along your final line. That way you can keep some of your madness straight.
I know that was a lot to cover for one day, but I hope it helps. Keep uploading your muslin pics to the Flickr Pool, and check back for a fabric cutting post later this week!