I don't generally care for sinamar in any beer of any kind, especially black IPAs. I used to much once in a beer. Despite it supposedly being flavorless, this is not true. Now I seem to be fairly sensitive to it and can usually pick it out in a beer. But that is just me.
Looking back through my recipes, about 60g or 2 ounces added to the top of the mash at the end of mashing is a "dash."