Finished sweater is too WIDE. What can be done?

Although I matched the gauge and followed the NORO pattern for my size, my finished pullover sweater needs the side seams taken in by at least 5 inches at each side of the bottom and tapered up to the armhole. It’s in stockinette. How can this be done gracefully? The yarn is 40% cotton, 30% silk, and 15% each wool and nylon. Should I do some sort of pre-shrinking first? HELP. Is this problem fatal?

For 5" I’d reknit it with a smaller size at the bottom edge and increase up to the correct size at the armholes… You can take up that much of a seam (2½" each side) then cut off the extra, but you need to be certain that’s going to come out the right size. It wouldn’t hurt to wash it first to see if it shrinks, grows or stretches more one way than another. Then see what size it comes out.

Well, I’m not really sure how much 5" is, but not much there can be done about the width. You can try to just make a deeper seam - and this will work if your yarn is… thin / fine.
One thing you can do is make a crocheted seam - this way if it really stretches more, or shrinks, you will be able to easily correct it. Like my idea here with the flexible width, but your “seam” will be in the inside.