You need to work it out yourself, there is no shot thats best for all ocasions. May be good to try to play the same weight all the time at the beginning to understand how the stones behave as its different in the centre line or on the side.
As to sweeping it straightens the curl a little so you can use it when the stone goes too narrow

I love takeouts. Unless absolutely necessary, never use max weight. Condition your trigger finger to release in between green draw and red max, so like in the yellow area. From there you will need to learn the curl on the ice to approximate how much you need. 

For a normal takeout that's 90% weight (I like those), the broom should be just off the edge of the outside of the rock in order to achieve an inside roll. For a nose hit, go a little further out. 

If you have questions challenge me sometime, I'll help you.