Hi KIWI I have a 92' motoryacht, and will be heading there in May. It's been a while. I remember lots of surge. Has any new dockage opened.
In May you might have a chance, especially if it's later in the month when things have quieted down. In general though there is no along side mooring, only Med-style. Unfortunately there is no new dockage areas in the Port of Gustavia, and yes there can be alot of surge in there, especially during the winter months. Good luck, and it might be worth it to buy a passarelle.
I once went 'side to' on the other side of the harbor. Don't remember contact info and don't want to do it again. The boss thought it would be a good idea and I didn't sleep well or much. While there a yacht on the other side med styled into the dock and left without the swim platform. anchoring is best in st. barts since I first went there in 1979.