Suppose that i want to box 6 horses. Is there any staking plans other than betting each of the 120 combinations and flexi betting

I'm thinking multiplying the prices -1 and dividing the result by say 10 in a 10 horse field

e.g.

((2.4*5.9*6.2*12.6*6.2*9.3)-1)/10

I plan to use excel to speed the process up.