This will be much easier than the changes on the lower part.
First, remember that we reduced the waist by 2 cm for the lower back, so we have to do the same for the upper back, of course, for the two pieces to fit together later on.
Since we need to insert the two darts that the Milford has got, anyway, this is very simple. We merely add the darts, (beginning exactly where the side pleats in the lower back start) and make them 2 cm wide at the base.
Based on picture analysis I draw those darts 21 cm long.
All right. The addition of these darts means, that the side seam will run where there’s the dotted red line in the pic on the
left hand side. You can see that I changed point S1 a little bit accordingly, by redrawing the side line that starts in T2 and goes through r, and determining the new position of S1 (4 cm from r, cf. Step IV).
Close up of the new position of S1.
The centre box pleat is added much in the same way as the one in the lower part was. I think a 3 cm wide pleat should suffice here (the left hand dotted red line marks the pleat’s later position, the ones on the right show the form of the pattern as we’ll have to cut it from the fabric). Determining the correct length of it is rather difficult but I estimate it’s about 30 cm (measured from the waist line).
And this is the finished master pattern for the upper part of the back now: