It depends on your fishing application.
Open water trolling:
Suffix 18lb test – dives approx. 4.5 feet per color when trolling at 2.0 mph
5 colors
20 lb mono backing
50 foot 10 lb leader (Berkley XT)
I will be doing some experimenting this weekend with the Suffix 832 leadcore. This line has more sensitivity, is stronger and dives deeper. More sensitivity may allow me to detect debris on my crankbaits. Stronger line is a good thing. Diving deeper may not make a difference in the open water other than having to put out less line. I also may not want that crankbait closer to the boat thinking it may spook more fish with boat motor noise in calmer conditions.
Contour/Structure Trolling:
Suffix 832 18 lb test – supposedly dives approx. 7 feet per color when trolling at 2.0 mph (I have not verified this)
4 colors
20 lb test mono backing
30 foot, 20 lb test / 6 lb diameter braid leader (spiderwire stealth)
This set up will give you more sensitivity and allow you to detect bottom and/or debris on your line.