Depends on following:
1. Exact resistance per foot,
2. Amount of current being drawn,
3. Is current PWM'd or linearly applied,
4. Amount of temp rise verus how much is lost via heat transfer in cutting process versus regained in free air.
5. Coefficent of thermal expansion of the material.
1, 2, 3 affect 4. Once you have 4, you can do some math after you confirm 5.
Don't have, can't find what's needed???
Resort to cut & try or try to find someone who's done it already.