Math Genome Fun

You have thirteen characters: the numbers 1-9 and the operators for Plus, Minus, Divide and Multiply. Arrange them in a string so they have the highest possible value, or write a program to do this for you. If a string cannot execute as a mathematical function, it scores zero.


Full list [1,2,3,4,5,6,7,8,9,+,-,*,/]

There are 13! possibilities. How many score more than 0 (are mathematically viable)? How many steps did you program take / candidates did it evaluate. How did you know when to stop?