Feature Request - Optimization strategy

[xal88]

Hi, thanks for the great piece of code.

Would be very nice to have an option for the solving method target.
At the moment you are minimizing the box area.

For my usecase I have a heigth_limit, and want to minimze the overall box width,
( This is an irrigation system, where height_limit is the pump volume, and box width is the watering time per circuit )
I had to change the solver energy def, but having an option for this would be very handy.

Kind regards
Alfred