Hi,
I think this can be solved very simple by expressing the divisor (DIV) as a polynomial, I made a polynomial of fourth degree for the divisor up to DIV=20 and it will be:
p=-6E-12*x^4 +7E-8*x^3+0.0003*x^2 +0.5536*x-143.05
where x=target and the divisor(DIV)=p
so the bet amount will be target/p and this polynomial will only be valid for DIV starting at 6. But you can make your own polynomial in Excel for your specific "average odds".