I usually back the brocade with lightweight iron-on interfacing. I use organdy or a very lightweight cotton for the lining.
I intend to close the shoulder seams using a ladder stitch because it is less bulky and will lay better on Gregor's shoulders. Note the red arrows that show where I trimmed back the seam allowance. The pattern outline can either be a sewing line or a cutting line for fabrics like Ultrasuede or leather. I have traced the pattern onto the back of the brocade fabric being careful to line up the brocade pattern.
Next I sew the outline of the vest being careful to leave an opening to turn-out the garment. Note the red arrows where I have left the opening and folded back the seam allowance. Note how the seam allowance has been trimmed to avoid any bulky corners.
I use forceps to turn out the vest and a pointed wooden dowel to push out the corners.
Then I steam the vest flat.
Looking at the enlarged detail of the shoulder seams you can see that the version on the right has the traditional sewn across with seam allowance closure. The shoulder seam on the left was closed using a ladder stitch which allows it to be less bulky.
The best thing about this pattern is how really easy it is to use in dozens of different ways -- for Gregor or even for Sasha.
Because of the way it is designed you can use stripes, or checks, or plaids and never have to worry about matching up the patterns. Designs can run vertical or horizontal and always work perfectly.
The two shoulder seams can be sewn two different ways depending on the fabric or your design. You can use the standard sewn across with seam allowance or you can cut off the seam allowance on the pattern and join the two sides using a ladder stitch, This allows you to use heavier fabrics like the brocade in the sample above and it also works if you want to make a reversible vest.