If you want to even out (for now) try adding a short piece of pig tail or something to the shortest line. It's probably a temporary fix. Is it the center line? Make sure the center lines are exactly the same when done, if so.
An inch or two on a front line makes a very big difference and is hard to compensate for while riding (especially unhooked with both hands in the middle) or at least a pain in the butt on the one side that keeps wanting to go in the water, then you turn around and it seems okay... maybe wanting to rise a little.
I think Best is working on getting an upgraded line option this season, because even Simon of Best admitted the stock line leaves room for improvement. I don't have stock line on my bars, I use Q line. Riding Tom's kite yesterday reminded me why.