If (that's if) there is any non-uniform grade distribution in...

If (that's if) there is any non-uniform grade distribution in the melt it will form layers in the bar like a stack of pancakes. A vertical cut will split the grade evenly.

Why are you fussing about the grade? It's ounce plus dirt! Millions of tonnes of it.

I wouldn't take too long deciding - bugger all shares for sale. Only ~8% free float and most of the the few available shares that are getting hoovered up will be tightly held.