Hi John, good to hear you are still keen, even after all those years, likewise!
Well, firstly you might want to update your windsurfing board too, if so then I would choose something like the new Jag 125, which could be a good option for both windfoiling and blasting, with your advanced slalom background/Jag is basically the newer Ray version. And then getting a Sky Wing in probably 6'0" or 5'8" size, depending on if you want to learn, progress and keep the same board for longer.
We also have combination boards like the Bee, which is a SUP which can be used for windfoiling, wingfoiling, sup foiling and sup, one of our best sellers currently. Our Foilstyler 102 is also a combo Wing/windfoiling board, but too small to learn both on, rather for more advanced riders.
In May we'll launch the new 2021 StingRay range, which has sizes which work great for both windfoiling and wingfoiling. So for your season in NZ that could be the right board, especially if you are not in a rush. Stay in touch with our NZ importers/shops, so they can pre-order you one of those!