Knowing, as I said, that the camera is usually smarter than me, I left it on "Evaluative", which meters the majority of the image. I wasn't taking photos of just the iron and flames, so taking all the lighting into account was important.
From there, I mainly left it on aperture priority- note the difference in clarity of the flames in my comparison pic below. Part of that was the much faster shutter speed in the "underexposed" image, which stopped the flames better.
I played with the aperture some- although my big lens at anything above 120mm is already f5.6- and predominantly used the exposure compensation to reduce the exposure. In Av, the compensation simply slows or speeds the shutter by a small percentage, under or over-exposing by that amount.
