Following the recipe provided in Cariadoc’s Miscellany as my guide, I’ve made a number of sekanjabin syrups.
Champagne vinegar + sage – I love this one
Red wine vinegar + mint + thai basil – I didn’t do a blind taste test, but it tastes an awful lot like the red wine vinegar + mint versions I’ve tried in the past
It is really easy to under-dilute both of these. But the problem is easily fixed by drinking/pouring some off and adding more water/sparking water.