I'm getting back into Great Lakes fishing.  I need to replace the line on my reels.  I've read a ton of discussion on types of line...but don't seem to see anything on how much.  After applying the backing, how much line is usually applied to ensure you don't get down to the backing?  I understand the random King that will take most of your line...but what is customary?  500ft?  1000?  I'd like to hear what you guys think.