from what i am seeing on the platinum, either one of those coils will need to be run in wattage mode - the kbox platinum does TC on Ni/ Ti only, unless I am missin' something... either of those coils would be good, i would recommend trying the stainless, but i am partial to stainless steel coils - very clean flavor, good vape... if it is a .5ohm coil, after installing and priming the coil, i would start around 20 watts and work up from therein 2-5 watt increments, until you find your 'sweet spot'