In the past, I have used twill tape, but the clear elastic doesn't add as much bulk to the seams. If you are not using either clear elastic or twill tape, at least do another row of stitches 1/8" away from your first to strengthen that shoulder seam and make your garment sturdier.
The next step in the instructions is to do the sleeves. Put in a gathering stitch between the notches and then line up the center of the sleeve with the shoulder seam and pin. This sleeve does not have a front or back as in some patterns.
I didn't bother to pin all the way around the sleeve, I just started sewing at the end and stopped when I got to the gathering stitches.
And then I pulled the bobbin thread right there to gather the fabric to fit the sleeve opening.
The rest of it is rather unscientific. I just gathered up the other side approximately the same amount and continued sewing.
Then, you sew down the length of the side seam, starting from the sleeve opening, past the armpit and down to the bottom of the shirt.
After I did all that, I tried it on to see what difference my new sleeve opening shape made.
Plenty of room!
But I have a good impression of a flying squirrel to show you...
That's not so attractive.
Remember how I said when we were putting the sleeve on that the front and back are both the same? Yes? Well, this is what you get when you essentially cut two fronts. Really, the front and back of a sleeve opening or armcsye, are two different shapes, one is usually shallower than the other.
I suddenly had the realization that this is the REAL reason for the drag lines from neck to armpit and the reason my sleeve looks a little twisty as well.
We must now consider this my third muslin. sigh.
At this point, if I wanted this to fit with no extra wrinkles at my armpits, I would need to redraw a different back piece and completely redraft the sleeve. I am not willing to do that. It's too bad that Jolijou left us with this conundrum. Shelly has so much potential. Nobody's perfect, right?
I went ahead and shaved some of the squirrel wing off and added the neckband. Here's my last pic for the day.