If you measure off your genoa, you will end up with a cruising spinnaker...better than a white sail but not a whole lot better. Its primarily a question of sail area. If you want some performance, you should consider a symmetric, or an asymmetric with a bow sprite, both would offer the large sail area needed to make off wind sail as much fun as upwind sailing. A asym is easier to handle.
Certified...in several regards...