The yardage requirements for this sweater will vary widely depending on the way you choose to approach the stripes and whether you are knitting the cropped vs. hip length version or the 3/4 vs. full length sleeves.
Total yardage for full length body and sleeves: 5 (5, 6,
6, 6, 7, 7) 8, 8, 9, 10, 11, 12) skeins 1250 (1300, 1450,
1500, 1550, 1700, 1800) 1900, 2000, 2300, 2500, 2700,
2900 yards Tanis Fiber Arts PureWash DK Weight yarn
(113 g = 260 yds).
For an even width stripe using 8 contrasting colours you will need between 25 & 50 yards of the cast on colour (smallest sizes vs. largest sizes) and 75 & 125 yards of the last stripe colour with the remainder of the yardage to be made up by your Main Colour.
If you are uncertain which size you should make I’d recommend going down a size for a good fit across the chest. Due to the biasing of the fabric in the yoke combined with the slight A-line created when you switch to the body portion the fit seems to air on the side of generous. Many knitters have had great success when sizing down rather than sizing up. Happy stitching!