> "Btw what solver did you use?"
I used the builtin [Excel Solver](https://support.office.com/en-us/article/Define-and-solve-a-problem-by-using-Solver-9ed03c9f-7caf-4d99-bb6d-078f96d1652c).
There is also an open Solver that I have yet to try: http://opensolver.org/
For awhile, I was using a Mathematica solver but it doesn't allow a correlation coefficient as a goal, only least squares. I think there is some property of using a correlation coefficient that allows a solver to avoid getting stuck in local minima. It may have to do with not having to worry about scaling at every step. The rescaling can always get done at the end.
There is also the Eureqa solver that I used early on, but that tool got bought out by another company and not sure of it's status. Eureqa allowed correlation coefficient and a whole range of optimization targets, including an interesting hybrid cc+leastSquares target. The architects of that tool understood the importance of providing different targets for optimization.
Probably should try using R and one of the solvers there, but I am in a mode of staying with what works for now