I would always prefer C25, BUT make sure you take the flux core. Also, add a fire extinguisher to your check list and welding blanket.

I've actually sat in a modified refrigerator cardboard box for a wind block (keep an eye for fire)

Maybe some 1/2" painters masking tape and anti-spatter spray if you really think there will be that much spatter. I use a small hobart with flux core all the time and other than a wire wheel, looks fine for paint.