I agree the luff tension on the stock Wave jib is a problem, but I think a bigger problem is that it is too close to the mast.

I played with attachment points using the spin pole and found once you get about 2 ft in front of the bow, the stock jib really starts pulling. With the attach point 4 ft in front of the bow, the effect of the jib is all out of proportion to it's size.

I have also tried racing the Wave with a stock jib against dinghies and found, the stock jib just plain makes the boat slower