Ah thanks I had totally forgotten about that
The AL value for those cores is 42. In my design I went for a target inductance about 13uH. This translates to 18 turns on these cores. According to my sims, we want about 30mohms DCR for optimum damping.
Looking at the mechanical data the core cross-section is 3.8mm X 6.35mm so a single turn would be about 20mm in length assuming zero wire diameter. Thus 18 turns is going to be 0.4m, roughly. We therefore need wire that's 75mohm/m and that works out to be 23AWG, allowing for terminations.