RE: Carve 122 and Severne sails
Both the NCX and Gator are good choices for the Carve122 in blasting and simple freestyle mode. NCX has a slightly larger foot area and crisper feel/handling with high% monofilm construction. Gator has a slightly higher foot for better maneuvers/tricks etc and more durable construction (but softer feel) due to the full laminate construction.
The other two Severne models to consider are S-2 and (e)lement, but considering your description of ridestyle/use, the best option wil come from NCX or Gator.
Cheers ~ Ian