user control of colors and line widths

[perrydolia]

I have written an efs that colors a line red if the swing is up and green if the swing is down.

The script works fine. I also understand that if I do not specify line colors or widths in premain, then the line can be colored etc through Edit Studies. But the color of the line will only be one color, not two colors for up swing vs down swing.

Is it possible to add instructions to the efs that make it possible for my users to use Edit Studies to assign two conditional colors to the line?

If so, how?

Thanks,

PD