Carolina leader matterial choice?

[keithdog]

I'm finally going to try using the carolina rig extensively. The trouble I've had with the weed killing thats gone on in my area lakes has fishing so screwed up I want to try a few new techniques and see if they work better than my normal approaches. I know how to rig and work the rigs pretty much but I'm not sure about what should be my choice of leader material. I am planning to use flourocarbon for the leader, but don't know what weight line I should use.
I'm fishing natural lakes without the structures you would find in man made impoundments. There are no flooded trees, deep creek channels, rock piles, submerged road beds or anything like that. I'll mostly be using the rigs around points, drop offs and deeper weedbeds if I can find any. I may use it around flats on overcast days and early in the mornings. Again, virtually no weed cover is left in the lakes. My gear will be as follows. A 7 foot Med. heavy IM8 graphite rod, a Cabelas Prodegy casting reel, loaded with 40 pound braid line to which I will tie the carolina rig. The 40 pound braid line sounds like overkill, but it's already on the reel for fishing in heavy cover and I figure it will telegraph well through the rod to detect any cover I may come in contact with as well as any pickups. Just not sure how heavy the leader line should be.