If you're trolling, using a leader will have essentially no effect on your catch rate for any species.  The fish does not have time to size up the bait.  The fish either commits to a strike or loses the opportunity to feed on a seemingly easy meal.

The Chrismar map is an excellent map for locating portages and seeing the entire park but if you will be on confusing lakes with lots of points/islands, or if you just would like to look at your map without squinting, pick up either McKenzie or Fisher maps that will give you a lot more detail, including some of the campsites in the area. 

If the McKenzie/Fisher maps disagree with the Chrismar on the location of a portage, it's been my experience that you should trust the Chrismar to be correct.  McKenzie's have topographical lines which are an additional aid to navigation. 

No map I've ever found has lake contours for the Quetico.