The heads are not available as stand-alone sales. By the nature of manufacturing, the heads vary in weight. Titleist puts them in bins by weight. Club orders can specify swing weight. As part of the production for custom orders Titleist will match up shafts, grips, and swing weight to assign the heads to achieve the balance specified.
If not otherwise specified or for retail sets, the SW will be built to D2-3.

Chris, for best results, recommend contacting Titleist customer service.

........at 800-333-4200, available Monday-Friday from 9:00AM - 5:00PM EST.