i dont put weights on my leader, a lot of guys do and still catch. But i like to keep it clean and free from any wear and tear so that it doesnt break on me when i have a fish on.
One thing that wasn't mentioned, i think, was depth...which plays a big deal. If your depth is off, even by an inch, you wont catch anything. Play around with it and see what works based on water levels, current and cover. Ideally you'd like to have the bait within a foot or less of the bottom
if you're curious, my set-up, which has remained nearly identical for the last 5 years is 1-2 foot leader of 6lb fluro (seaguar), tied to main line with a swivel and weights only on main line. Bait of choice across all bodies of water is a 8mm or 10mm(dirtier water) chartreuse bead w/ size12 hook