Can you not make it work with just the Stiggins and no mescal or agricole? But it should be easy enough to find an agricole blanc locally, right? Clement at 100 proof is pretty common here and I have also seen Rhum JM and La Favorite on occasion, maybe even Damoiseau. In the islands they are typically around 110 proof (provides some lovely viscosity!) but here in the US we are usually lucky if we get 100 proof. Boston selection has to be as good or better than Atlanta?
I just got a bottle of the new St. George Bruto Americano that might be worth playing with in something like this.
