I understand how the zone system works by exposing for the shadows and developing for the highlights but what happens if I use coloured filters to further alter the tones.

How does one know how many stops a coloured filter will lighten or darken certain colours in a scene after the filter factor has been applied? For example if a green filter is used on a landscape scene, the grass will be lightened and the blue sky darkened but is there a way to measure this?

Edit: I just thought should one take their spot metre readings through the filter?