Hi, I am about to run out of Pierre Ferrand and was thinking of trying a different Curacao, however I noticed a very broad spread of ABVs.in your top 10, some as low as 25%
What would you do with the recipe with lower ABV Curacao? Or should I just get the PF again

I actually swear I read that page and I didn't see the icing sugar bit, may have been a while back when I first thought about this drink. The wider internet says granulated and icing it's "the same" but Simon is right, there is 2 to 3% anti caking agent.
I actually usually use sugar syrup prepared in the proportions according to Simon's recipe, subbing a cane/white sugar syrup blend in most cocktails except ones where the clarity is useful and I use white (again prepared fresh as per Simon's 2 to 1 recipe)
Having now tried the home prepared white sugar syrup alongside the powered sugar, in this drink, I'd say it's not worth the effort, the syrup is fractionally better when done side by side

Is icing sugar an equivalent of the powdered sugar called for? Any disadvantage to using here?

Just to confirm, that this is served with no ice in the glass?