Blue Book waistcoat cont'

Continuing on with the Blue Book waistcoat, you can see that the balance is off . In the top photo the fronts are short and are pulling up causing an excess of fabric in the back armhole, a diagonal tension from mid back to front of armhole and if you can see it, my waistline is tilted upward.

In this photo, I have unpinned the shoulders and pulled the front of the waistcoat down so the tension line disappears and the waistline drops into a more pleasing line. The CF stays on the CF line in doing this. This reduces the excess at the back armhole, and releases some fabric below the shoulder blade which I have pinned (a belt at the back waist would be used to draw this excess in)
I have tried to keep the shoulder in alignment so that I have not changed the neck point position yet. You can see that it has dropped a full 1.5cm (5/8").

If you look at the fronts in profile you can see there is still an excess of fabric in the front neckline that needs to be dealt with somehow. The question is how. The answer depends a lot on your fabric. Can it shrink in enough?

Honestly I would love to get a good wool that would, but it is a lot to shrink in- almost a full 2.5cm (1"), so it seems unlikely. Besides, we're as likely to get something strange like- well, I don't know- lame, or velvet, so another way of dealing with it is necessary.