As with
regular chunk candles, pour the overpour over the chunks. I like to pour a bit hotter than normal...about 180-190 degrees. This helps the overpour get around the chunks a bit better.
If you're going for more of a rustic pillar or votive look. Pour at 160-170 degrees...or even better yet, chill the molds and then pour the overpour.
In this particular example, you'll notice I've made dark blue chunks with a light blue overpour. In the multi-colored example in the Vertical Chunk Candle Gallery, I've used a white (no color) overpour so as to not obscure the chunks at all.