Transparent effect

Hi (I don't know if this is the right forum to ask). My players are about to start a series of gang feuds, and I wanted to use a map to show them which areas are controlled by the different factions  when I move the selection to token level the color becomes too "obscuring", and you can't see anything anymore Any ideas on how I can resolve the situation?

Select your polygon and open the color picker menu for the fill color. Click in the hex code area and add a two-digit number at the end to represent the opacity level, then press Enter. Example:

it works, thanks!