Jack, I just really like turbinado sugar. It adds a little depth. And yes, it does take some extra effort to get it to dissolve but the end results, to me anyway, justifies the extra effort.
I have made it with Bourbon (usually OWA) and it is really, really good. It is a tad on the sweet side, though. The orange bitters I have isn't nearly as herbal as regular Angostura bitters though it isn't bad with either...



