Inari: A Tale of Five and a Half Muslins

I love the Inari dress by Named Clothing. It's simple, it's modern, and it looks good on nearly every single person.
But I'm aware of my fitting issues: I know that my bust is proportionally larger than my other measurements. I know that my shoulders are pretty narrow, and so is my underbust. With this is mind, I ordered the Inari PDF pattern. In English, mind you, though speaking Finnish would be pretty cool.
Picture is from Named Clothing's website.

After I got it I deliberated over sizing for at least half an hour, before I decided that I needed more info and contacted the company ( at 10:00 at night my time). I asked for high bust, cup size, and under bust measurements, and the awesome ladies of Named replied quite promptly, considering the time difference. ( I received the email back at 4:20 AM. )
I looked at the measurements, remeasured myself in centimeters for precision, and compared everything. For every single measurement I was in between a 2 and a 4. I was closer to a 4, by about 1 cm, so that's what I decided on. You would think that with all my thoughtful preparation it would turn out halfway decent, right ?
Blame it on my shoulders.
They're, like, two sizes smaller than the dress. At least. the dress was just too wide. The armholes were a bit big, too. What with the fabric I used, I felt like a poorly clad hospital patient.
Also, Named drafts for the height of 5'8", which I am shorter than by about 5", so the length didn't work either. But that's an easy fix.
The shoulders! They're not.
So, I sadly printed the pattern out again, this time with a size 0 and a 2. I blended from a zero at shoulders and armholes to a two at waist and down.
And the shoulders were too tight. I could barely raise my arms 90 degrees.
Just for kicks and suffering, I then modified my size four pattern to a size two and made that. 
It was a big NO. The shoulders, strangely, were simultaneously too small and too big. I couldn't raise my arms well, but the fabric at the back of my neck was gaping.
I decided then to start with the 0/2 and fit it.
First, I did a broad back adjustment, courtesy of Kestrel Makes. Muslin 4 improved the fit, but not enough.

I found this article about sleeves/armscyes by Fashion Incubator and took the plunge.
I redrafted the armholes and raised them, maybe half an inch ? I took off a good amount of sleeve cap ease as well.


Then came muslin 5. I ran out of fabric I was willing to cut up here and had to ask my mom if she had any sheets I could use. Luckily, she did. (Worn-out sheets are super comfy muslin fabric, by the way.) It was better. But still, I could not raise my arms.
At this point, you're probably wondering why I need to move my arms so much. Well, I work in a library. I put books/movies away for a good portion of my work day. I'm already short -- reaching those upper shelves can be hard. It doesn't need to be made harder by the fact that my dress won't move with me. This is why I care so much about mobility of arms in my Inari.
After a bit of thought, and reflecting on the Fashion Incubator article, I decided to angle my sleeve, so the center wasn't actually at the center.
KABOOM !!! It worked. Granted, I think I moved mine a bit too much, so it sat awkwardly when I wasn't reaching, but no back strain was happening ! I did it !
I have never put this much effort into something before.