Tim: New tire on front, old on back? I briefly had a problem like you're describing with mismatched tires, but I've yet to run into anyone else who had an identical problem, I only found out by accident myself when I picked up a nail in the rear and had to replace it- the wobble disappeared. Of course, that was with Dunlops, too. I'd personally not loosen any fork clamps unless you're totally convinced they're over torqued or something.
My 0.02