The shims come with the pad, and the ones that come with it are plenty. As for availability do the email notification, and be ready to jump on it when it does become available.
So many options. For a quick fix I cut wooden dowels and shaped to fit the top of my stock, taped them down, covered with a beartooth cover.
I am not a big fan of the kydex style so I build my own or use loggerhead inserts.
I will probably finish a loggerhead install tonight if I don't get any distractions. I like their product since it is a 1 bolt adjustment instead of 2 like mine and mine takes a lot of milling fitting. Both seem to turn out fine.
Here is one I finished with my set up: