I don't know about a usage matrix, but I can coment on the redundancy. "Two is one; One is none."<br><br>For a PSK, you want it to be as versitile as you can, but for fire and signalling, you want all the options you can get. A singel match is non-redundant. But you wouldn't want to be stuck to just that. Or just to matches. Sometimes might have plenty of time until dark, and no immediate concern about cold, but you will want to have a fire up and going pretty soon in a lot of situations, so you the sparkright or the spark or MFS from your kit. Those aslo serve if you are in trouble long enough to be out of matches, or they get soaked despite all you attempts to water tight the kit and make the matches waterproof.<br><br>Fire is the most rundedant thing in the PSK, and for good reason.