I have finished installing beadboard panels in a small bathroom. I am now adding a 1 x 3 shelf on the top all the way around the beadboard. The problem I have encountered is one of the walls has a curve to it. I have cut the 1 x 3 and placed at the top to find out that in the middle of the wall there is a one inch gap from the back of the shelf board and the wall. What should I do to fix this gap? Should I just fill it with caulk or try to fill this gap with something else? I thought about putting another piece of trim on top of the shelf where it meets the wall but that doesn't look very good. Any help will be appreciated.