Just make sure you have non-coated stainless steel when building coils!
More info below:
Haven't made any specifically for the kangertech RBA plus, but I have used Stainless steel for coils quite a many times. Just keep the build above the mod's lowest firing resistance and be sure to use good grade high-amp drain batteries and you'll be golden. SS usually heats up and cools down faster than Kanthal, so good wicking is usually required for SS to work properly. It also has got lower resistance when compared to Kanthal, so you need more wraps when building. If you can fit a SS-coil inside the RBA plus, then there's no real danger of using a stainless steel coil.
I've built coils with max surface area, mostly using 0.6mm SS317L, 13-wrap dualcoil wrapped on a 2.5mm coiler should bring the resistance to somewhere in between 0.2 and 0.25