Obviously this guy hasn't seen a somewhat used clone. I've seen more than 1 that was used enough that the copper or brass plating wore off enough for the bare steel to show through. Chances are he's testing a ss tube, a copper plated ss tube, and a brass plated ss tube.
And if solid core wire made any difference in the world vs stranded wire, don't you think every single SPL audio competitor in the world would use solid power cables running to their amplifiers? Those guys are 20 levels above anal when it comes to getting every single milliamp to their amps