Is that 1/16" along the entire length of the counterweight? If it is 1/8" at the back of the horizontal stab and narrower near the front, you can adjust the hinges to make it straighter. Inboard should be shorter and/or outer longer to angle the counterweight outward. If the counterweight is already parallel to the stabilizer tip, then you could check the hinge brackets for square or (carefully!) bend them to be just a bit more outboard. Or you could remove 1/32" from both the counterweight skin and the horizontal stab skin. Personally, if I found the hinge brackets to be perpendicular to the rear spar, I'd trim the skins rather than tweak the brackets.