I'm not understanding what you did. How did moving the tack of the jib forward (attachment point of the furler) change the angle of the mast? Seems to me that mast angle (not pre-bend) would only change with adjustment to the jib and aft stays. I would love to see pictures of your setup showing the jib stay and the roller/furler attachments. Also comparison of the sails pulling in the same manner as the pics you previously provided which seems to indicate the luff of both main and jib to be a little soft.
I was able to improve my weather helm problems with a new sail (mine was much baggier than yours) but still have pretty strong weather helm in heavier gusts, which I have always considered a necessary evil. If I could tune them down a little I would be much happier.