TOL, if you want, you can simply use your normal 20lb mono trace with a short 6" 60lb fluro trace to the slug, just join them with a 3 turn surgeons knot like this http://www.animatedknots.com/surgeonsjoin/index.php
you wont lose a lot of casting distance with this and the fluro will be tougher than just the 20lb trace... or dont worry about fluro, if you lose some slugs you will have an excuse to buy some more
mike