However sweet, where does it say in the Bible God won’t judge you more harshly than you judge yourself?
I know, I was surprised too. But I'm Catholic, we have Priests, if they're going to tell me something then unless it's utterly awful I'll roll with it.
The New Testament depiction of God isn't as violent in his depiction as the Old Testament one.
He gives us Jesus who gives us an out from most of the judgement if we follow Him. But even in the OT, most of the time repentance makes things ok sooner or later (if they get the chance.)
How do you decide which parts to take literally and which parts metaphorically and which parts to totally ignore?
I try and do most of it really except the cutting off my arm bit, because I seem to be one of the few people that ever thought of that as what should be part of the Christian rules. 
The only other bit I'll never do is give any husband I might have in future sex when I'm not in the mood. I'd rather be single for life. I explained to a Priest that I would find it very psychologically unpleasant and he said a husband is supposed to care for his wife, so shouldn't expect that of me.
Catholicism is surprisingly laid back in some respects or at least can be. Though I did come across someone on Youtube who said not shagging your husband on demand is a mortal sin. 