My rule of thumb is that if the chink line is 3/4” or wider, use chink. If the chink line is less than 3/4”, use caulk. The chink is made to flex in a wider strip. We like to stain on top of caulk since the stain will help hide all of those little lines. It is customer preference when it comes to chink. Some people do not like the look of exposed chink lines. Another rule of thumb is, the fewer the chink lines, the better it will look on top of the stain.