you don't need the locking plug, a regular 1/4" plug clicks in tightly and holds just fine.
i made myself a couple cables for my G75 with just regular switchcraft #280 plugs, using right angle plugs on the other end to go into my guitars.
a quick google search shows the switchcraft #298 locking plug to be stereo, which you don't want. you also don't want to bother with non-switchcraft cheapies.
i'd take regular switchcraft over locking also-ran any day.