I tend to view TFN tutorials as a bit of a guide and then go off and experiment. My methods are probably not the best but I get results, If a like I can help you out with a step by step guide. At least on the way i do sabers. Generally I create some fresh layers and assign them later [ie: screen] and I don't really use the line tool for anything, I'd highlight the original core [white area] with the magic wand and use that as a guide.