Depending on exactly when in May you want to go, St Regis has a Free Night + Free Half Board offer on the Marriott STARS rate for stays starting after May 10th 2022. Might be worth taking in to consideration in the calculations, especially when considering the cost of 4 adult transfers between islands. It's certainly the best Bonvoy resort there (along with RC).
________________________
Founder of RWRD Travel, a Virtuoso member. For Four Seasons PP, Hyatt Prive, Marriott Stars or other preferred program bookings, please request a quote here.