If you will be painting, especially a darker color, you are okay not worrying about it. Panel lines are not that visible on darker paints, like OD, especially in areas like tail that didn't get that many fluids and crud on them. I know some folks believe you should always accent panel lines, but look at pictures of the 1:1 planes in service and decide for yourself whether panel lines are necessary.
Also, there are two kinds of panel lines- one around removable access panels, others just between two pieces of aluminum riveted to framework. Latter are much less visible. Many aircraft tail surfaces lacked much in way of access panels.