Which mast to chose for north iq 9,0?

I have bought a second-hand north sails iq 9,0 and I need a decent mast. North recommends a viper race 510 or a xc80 510, but those are pretty expensive masts if I have to buy them new. Therefore I want to buy a second hand mast or a cheaper new one. I can buy a second hand neilpryde pro race (100% carbon) for the same price as a new north sting 50, which mast should I choose? I think the north will have a better curve, but the neilpryde has the better performance. Which combination will have the best performance?

I think the North will work better because of the better match in bend curve. The Neil Pryde race pro has been described as a flex top.

Since you are in Europe, have you tried calling German windsurfing shops that sell last year's equipment? They might have excellent deals on Viper and Excellerator masts. I have bought my sails and masts from