They were so huge, I could have set sail on a windy day. Remove 4 side button plackets; remove 4 inches total from width and try again. After all that seam ripping and placket applying agony, they now fit even better than the first two pairs, since I was able to pin the side seams to fit exactly. Front fly pants are much easier to fit for that reason; on these pants the plackets at the sides are finished first and there is only so much help you can get from adjusting back darts (yes, I tried that...).
One happy side effect of the seam allowance mishap is that after adding an extra seam allowance to both the top and bottom of the waistband, the waistband is much wider (1.5 inches; 3 cm) and I really like it this way.