Hi rossfree,
I was just wondering if you had tried sandwitching 2 of these SS strips together with some heat sink compound and (mica ?) insulators so you could heat one with current and measure the hot resistance of the other one ? It seems to me you could then allow adequate time for heat saturation to get an accurate idea of the hot resistance of the strip. Other methods might be to insert strip into a heat treat oven while wired to an ohmmeter. If you do not have one, I'll bet your local junior college does and pizza seems to be their official currency .
JS