Sterling Silver, Copper and Bronze are very forgiving metal. Starting with the different metal sheets, my jewelry process includes hammering, pickling, annealing and adding texture. This "work hardens" the metal. I generally use 18 to 20 gauge copper for cuffs.
Generally speaking, sizing for women's bracelets usually are: Small wrists (6 to 6 1/2 inches); Medium wrists (6 1/2 to 7 1/4 inches), and Large Wrists (over 7 1/4 inches). As a general rule, I design my cuffs for an average Women's size which is 6 3/4 to 7 1/4 inches.
Jewelry Talk / sizing of cuff