I've used heat shrink hundreds of times and mostly used a wooden match, either the regular kitchen type or somewhat bigger strike anywhere. Sometimes I even use a propane torch when I have a lot to do but like to save the propane so I can start my charcoal grill. Works everytime. Just don't get the tubing too hot or it'll look sloppy. Usually standard shrink tubing will shrink down to 50% of its diameter & there is also molded shrink tubing if there is a significant difference in diameter between the wire (cable) and the spade. There is also shrink tubing that has an adhesive that is released when heated to provide a better seal & more secure connection. If you want to just color code the ends that's pretty straight forward but if you want the shrink tubing to help provide a seal and/or strain relief you might want to consult with your local electrical supply house to see what they offer & recommend.
