In either heaven or hell would an individual receive differing amounts of
reward/punishment depending on how that individual lived his/her life? For
example, someone who committed countless atrocities vs. someone who committed
the minimal amount of sins to go to hell – would one receive more punishment
than the other? Also, do you feel one hundred percent justified in knowing the
true nature of the good life (the life God wants you to live)? (I have a hunch
that you wouldn’t because that would be tantamount to knowing the mind of God).
Lastly, could you comment on the view of any other religious denominations
concerning these topics (even general accounts)?
In regard to receiving differing levels of punishment or reward in Hell or Heaven, respectively, that was certainly the vision of Dante in his Divine Comedy. He broke Heaven, Hell and Purgatory into nine levels each. Dante’s visions would most likely be the most developed, even today, of the vision of heaven and hell as you describe.
As far as official Church teaching, the best place to start a quest for answers would be in the Catechism of the Catholic Church, specifically paragraphs 1020-1060. (The Catechism is organized, like nearly all Church documents, by paragraph due to the multitudes of translations needed for worldwide distribution and use.)
The most pertinent of ideas for your questions are that each person goes through a particular judgment at the moment of their death. The question that must be answered is how that person has responded to the particular graces that God has offered to him or her during life. If the person had a complete response to these graces, they will be ushered in to the Kingdom of Heaven. (The Church’s teaching would say that this was only done by one person beside Christ, Mary.) If the person had a life of responding to the graces that God offered, but yet not in a perfect way, they would undergo a period of purification to be able to join in the wonderful Kingdom of Heaven, hence Purgatory. It can be summed up rather crudely by saying that you are on the way to heaven, but you have to be cleaned up a bit first.) Lastly, if the person did not respond whatsoever to the graces that God offered during life, their pattern of life would be such that they could not accept that grace after death, and then would be banished outside of the Kingdom of Heaven, hence Hell.
One last thing to keep in mind, Hell is not an absence of God. It is the realization that I have lived my life as if there were, and now I am forced to come to grips with that as a mistake in life.