After reading your post I came across this great picture on Sailing Anarchy. Note the scallops in the luff. That is pretty much what halyard tension should look like. Having said that, over tensioning should not make it too hard to furl. Is there any interference with the swivel at the masthead? Hard to see that high up on a 47 foot boat. One of the jibs on the C&C 115 I race on had that problem and the halyard tension had to be released to furl the jib. The other jib (heavy dacron) we used did not have that problem as it was a bit shorter in the luff.