Move _zombiemode_perks.gsc from raw/maps to mod/maps. Then open it and find the four shader precache lines from line 29 to 32. Change the values inside to your perk shader materials. Then scroll down to the perk_hud_create() function(should start at line 830). Inside you should see four instances of:
Code Snippet
Plaintext
shader = "*SHADERNAME*"
Change *SHADERNAME* to the name of your shader for each instance. Make sure you have added the shaders to your CSV and you're good to go.