At 0.9Ω, a dual, 2mm ID, parallel coil build, using either 29, 30 or 31 gauge Kanthal A1 wire, with a net 10mm leg length will produce a heat flux of 161, 227 and 322 mW/mm2 respectively.
Heat flux is the coil(s) radiant temperature, expressed in milliwatts per millimeter squared. Adjusting resistance up or down by as little as one tenth of an ohm will affect heat flux considerably.
To better understand what heat flux, among other variables are... along with the Steam Engine (SE) link provided by terry (and also the first hyperlink sigline below) click on the second sigline hyperlink, where I've written a SE basic to advanced user guide.
When you're done reading... you'll understand the relationship between wire gauge and length, multiple parallel coil count, net resistance... along with wattage output and their effects on heat flux, heat capacity and leg power loss.