I bought a DVD that is basically a wonderful tour of the Holland & Holland factory. Each step of the gunmaking process is explained. The workmen are all using an oil lamp to generate soot to help them with inletting. I bought an oil lamp on Ebay and I have filled it with lamp oil. I am not getting the amount of soot that they were getting at H&H. Is the height of the wick critical or is it type of oil that is needed to genereate adequate soot?