i was commenting about dundee being glad this wasn't on sixofspade's quiz..
ok, these aren't informed guesses.
detect illusion is capable of breaking past improved invisible creatures with spell immunity divination like the ones in tactics mod. the higher the score, the faster it is.
move silently will decrease the time between a backstab attack and rehiding in shadows as per another thread where someone extensively tested this, and published results.
picking locks over 100%...does not help..you can open any lock in the game at 100%
picking pockets over 100% doesn't help much either...a few characters, like ribaud has a chance of detecting a pickpocket at 100%, but that's what potions are for.