Configurable yarn / fabric, yards by color, dye-lot warnings, swatch ordering?

Yarn and fabric aren’t bought by “1 unit”, they’re bought by yards or skeins per color, often across 2-6 colorways in a single project. Forcing customers into one-line-item-per-yardage breaks the UX and inflates return rate.

The Magento configurator I build for this:

• Multi-colorway picker in one step, customer picks the yarn (e.g. Lion Brand Wool-Ease Worsted), sees a color grid, clicks each color and inputs yardage per color in the same UI. Cart shows one line per colorway with the total computed live.
• Dye-lot warning, matters for knitters and weavers. If the customer orders 6 skeins of the same color, the system checks current dye-lot inventory and warns if those 6 skeins would ship from 2+ different dye lots (visible color shift in finished project). Customer can opt to ship-from-one-lot (may be back-ordered) or accept the mixed dye lots.
• Free swatch ordering, $1 + ground postage for a 3"x3" swatch. PDP CTA “Order a swatch first” for fabrics >$15/yd. Cuts fabric return rate ~28% in my data, ~15% on yarn.
• Yardage calculator on PDP, “how many yards do I need for a queen-size quilt?” calculator. Tied to pattern templates with default yardages.

Technically this is a custom Hyvä PDP variant on top of Magento configurable products with a custom JS layer for the live cart computation. ~$3k, $8k of dev work depending on category complexity. Pays back inside 6 months at $500k+ GMV.