Every length hangs from the same edge of the door. Twelve inches is the standard and right for most doors. Sixteen hangs the wreath lower. Twenty-five and a half is for tall doors, or a wreath hung low.
Stainless is the bare steel, brushed. The colors are powder-coated over the same steel, so the finish is part of the piece, not a wrap.
Cut, bent once, and finished. Nothing to assemble, nothing to lose, nothing to crack in the cold.