If you aren't gonna help then don't utter nonesense. The question isn't "how can I get more spin from my prestige". 18X20 is relatively open? By whose definition? Its pretty much the most closed string pattern you can get, especially in the prestige.
To answer the original question, you can try the Prestige Classic Tour. Its 18X19 in a 102 head. There are few racquets that flex the way a Prestige does, none from Head with a 16X19. You can try the Slazenger PB to see if that's close to what you want, its 16X18. The VEngine isn't quite the same flex but you might like what you find with it, so its worth a try. Really can't think of any other racquets that may be the answer to your question. I would also recommend demoing TF TFeel 305 and nSix-One 95 to see if that's what you are looking for.