I've been using black iron wire 14 mils in diameter (30 gage?)to
replace grab irons.

I bought a spool of it for >$3 from McMaster Carr.

It's a little too large in diameter but it's black as midnight. It
looks particularly good as grab irons on reefers. I don't know how
it paints.

I've tried without success to find similar wire in smaller diameter.

This wire is very soft, comparable to the horrible green florists'
wire found in older kits.

Ed