You should calculate the RMS inductor current based on the waveform. Having the RMS value, to get the copper area you can use the formula A = I / J, where A is the conductor's cross section area, I is the RMS current and J is the current density. As a rule thumb, J should not exceed 4,5 A/mm². As lower J goes, fewer are copper losses and the inductor will dissipate less heat.
Another thing to take into account is the skin effect, which reduces the effective copper area due to high frequency. The maximum wire diameter can be calculated as:
Dmax = 2 x 76 / sqrt(fsw)
Where D is the maximum diameter in mm and fsw is the switching frequency in Hertz.
If the required area is greater than the area of a single conductor with diameter Dmax, you should use paralleled condcutors of less diameter.