Big float (9.0g or more) and bulk shot the hell out of it right above the leader... You need to get it down and keep it down. Also, don't cast upstream, you'll have way better control of the setup if you cast horizontally or slightly down stream from your standing position. I don't start trotting until the float is out of the fast water and into the seam (I keep pressure on it and swing it across). This way you know the bait is downstream when the drift starts...
Lots of shot, lots of trotting, and hold on.
I wasted HOURS the other day with a rig that was only slightly wrong. Buddy if mine gave me a couple of tips and what do you know, 3 drifts later I'm into one..