I like the Orvis Big game 50#. Thinner than 20# dacron. Kindof like having your cake and eating it too. It is expensive. Knots are a little tricky and you have to be very consciouse of winding it on tight and crossing it over its self.Otherwise it will dig into its self and that is a mess.
I think that the thin backing is the obviouse partner to the LA. reel. As a fish takes off, you loose a smaller % of your diameter, and LA. reels usually are a little short on capacity any way.