Okay, to answer your original request. These are the steps I use to easily locate and change a config for a FTB Packs.
1) On the FTB Launcher window, before you launch your instance, highlight your chosen pack and then click on
the Edit Mod Pack button situated below the orange OPTIONS and MODPACKS buttons.
2) On the Mod Pack Editor window that pops, up, click on the Open Folder button at the bottom left.
This will bring you to the folder on your computer where the instance you first highlighted (Monster, or Direwolf20 for example) is installed.
The addess bar will look something like this :
C:\Users\Owner\Documents\My Games\Feed the Beast Stuff\Monster\minecraft\mods
3) You will want to go up a folder level and if using windows7 you can just click on the \minecraft\ in the address bar to go to that particular folder.
This will give you the list of folders as follows :
configs
coremods
crash-reports
CustomDISkins
dumps
mods
etc
4) In the configs folder, scroll down to the Thaumcraft file and double click it. It should automatically open in Notebook or some other text editor.
5) Scroll down to the section of the config file you want to tweak, change things to your preferences, safe the file and start your instance.
####################
# taint
#===================
# Biomes and effects
####################
taint {
# Eerie biome id
I:biome_eerie=164
# Magical Forest biome id
I:biome_magical_forest=163
# Taint biome id
I:biome_taint=162
# The chance per chunk (1 in n) of a Taint biome spawning during world gen. Setting it to 0 prevents the spawning of Taint biomes.
I:biome_taint_chance=2000
# Can Taint be caused by flux effects.
B:biome_taint_from_flux=false
# The chance per block update (1 in n) of the Taint biome spreading. Setting it to 0 prevents the spread of Taint biomes.
I:biome_taint_spread=0
}
These are the settings for Monster 1.1.0. As you can see Taint spread is already turned off. Not sure about the other packs.
>_< Eeps, just noticed this is a necroed thread.