LD1, I use store bought lamp oil and just hold the part very close to the wick, causing incomplete combustion of the oil, leaving a good coating of black soot. You might trim the wick properly--with a pair of sissors cut off the square corners of the wick about 45 degrees. That'll give you a much narrower flame. Bet if you googled "wick trimming" or something like that you'd get a picture. Be sure to wipe off the soot every once in a while cause it tends to build up and give false readings. Sometimes I use inletting black. Both are messy though.
