Makes a huge difference the order you build the drink in my experience. I add the gin to the peel and agitate a bit to maximise early extraction of the orange oils before building the rest of the drink.
A slightly stronger orange peel flavour lets the bitterness Campari down easier into an almost marmaladey place for me. Generally feel like this develops in the glass, but why not enjoy maximally from the first sip?
Tom Bardman
United Kingdom