Do I need to manually change the skillMax, attrMax and attrCap in nGCDCalc ini if i'm using uncapper? Ini says that they should be set to 200...
If you set the SimpleUncapper option in nGCD.ini, those settings are automatically changed. However, in the current version you should change LevelFactor in nGCDCalc.ini; I recommend 1.5 for use with uncapper.
I'm using OOO and according to TesEdit progress.esm values are overriden by OOO values - does this actually affect Progress values in-game?
Progress hard-sets a bunch of values to zero so that you won't get weird behavior before its scripts initialize -- OOO overwrites those settings if it loads after Progress. After loading a save, if you get sudden skill-ups or see strange things when looking at your character sheet
during the first 5 seconds of gameplay, that's the reason. After five seconds all the scripts are running and Progress takes over completely. It's safe if you just don't do anything for 5 seconds after loading, which is a good idea for many other scripted mods anyway.
update: also, my level bar fills only 4% per skill, is this normal? is it safe to set nGCD.iLevelMode to 1?
Reduced advancement rate is normal. Changing the level mode is safe but I haven't done extensive balance testing -- it might need an even lower LevelFactor, but I'm not sure. Of course, it depends on how much of a challenge you enjoy!
also, are there any specific values to make progress work with nGCD?
There used to be, but not anymore! nGCD will override the settings that matter to it.