I know one of the big issues with an ALPS cap group buy is that older boards tend to use ALPS-style stabilizers, and newer ones use Costar-style ones.
Costar stabilizers, the insert is closed; on Alps stabilizers, one side of the insert is open so the whole assembly can slide over the stabilizer wire.
What would happen if you installed a Costar stabilizer insert in a cap, but cut one end open... thus giving you a shape similar to an ALPS-style stabilizer?
I don't really have a good board to try it on-- the ones I have tend to be Costar-stabilizers.