The Booze

Orujo de Hierbas is an herbal infusion of orujo which is also referred to as aguardiente, marc or grappa.  According to Wikipedia:

Orujo is a liquor obtained from the distillation of the pomace (solid remains left after pressing) of the grape. It is a transparent spirit with an alcohol content over 50% (100° proof). Its name comes from the expression "aguardiente de orujo" (pomace eau-de-vie).

So the first step was locating an appropriate base for my hierbas.  I was able to locate a Basque product from the French side of the border called  Marc d'Irouléguy from Etienne Brana.  Sam's Wine in Chicago sold it for approximately US$26.  Whilst it is not Spanish in origin, this product's Basque heritage gave me comfort that the finished product would not be too far afield of actual Spanish orujo.

Other options were limited.  I did see that Binny's offered an actual Spanish orujo from Fonte do Mino for a few dollars less.  Something else to try in future batches.

Thus having secured the base of my hierbas I was ready to tackle adaptation of the recipes.