If you find a way to purchase, please let me know - as I’m sure I’ll want to tinker with my swingweight. I was hoping that Titleist would stay with the same slider/weights as the GT, but that didn’t happen. With the GT, the only way to purchase for the first 6 months after the driver was released was to go through a fitter with access to their internal catalogue. For those of us living in the country well away from any fitters, it’s lead tape time until the online vendors start selling them.

The official release date is 6/11. There is an online custom catalog typically updated after new shafts are approved, but it also includes the stock numbers. It moves around the website, but I usually find it by trying to customize a club and finding a link there.
I have had to work with pro shops for an item. Large retailers generally don’t bother to order items not on their shelf I expect the weight kit options won’t appear before 6/11 at the earliest.