In rivers, the bottom current flow can be different than the surface flow. To help compensate, space your weights out about 10" or so along the main line, starting with the smallest 12" from the hook. This will help keep your line vertical and make the bait appear more natural.
Boat position at the location you've chosen is the most important thing. Approach the windward side of a shallow hump or reef, anchor about 50 feet away, and let out the anchor rope until you're within casting distance.
If you plan to drift the rig over a hump or reef, on the windward side, anchor directly in front of the target. This way there won't be an arc of line to reel up when the time comes.
On windy days, the action of wind and water can stir up insects and other creatures and push them over the top to the backside, attracting baitfish, and, in turn, their bigger cousins. Don't overlook the backside of shallow reefs and humps.
Slip-floats are good for use with hellgrammites and crayfish. Holding them above the bottom and rocks doesn't allow them to grab hold and dig in.
A couple of ways to slow down the drift of your float:
1: Use a smaller float. They're less affected by the wind.
2: Get a float with a lead or metal sleeve. Not only will it ride lower in the water, it'll increase your casting distance.
3: Use a wood float. They're more dense and will ride lower in the water.
4: Add more weight to your line.
Sometimes we get snagged and have to break off the line. To try and save your float, slide a rubber stop onto your line a couple of inches above the weight. That way if the line breaks at the weight or below, the stop should keep the float from sliding off your line.
If you've lost, or broke, all your floats, you can use a fixed float as a kind of slip-bobber. Just depress the button and turn it 180 degrees so the metal loop doesn't seat. Put your line through and add stops, etc. It ain't pretty, but it'll work.
This rig also works well for fishing eddies. Just set the depth, cast it out, and let it float around and around and...
If your fishing for bass, sometimes you can trigger a strike by hopping the bait on the retrieve, kind of like using a Carolina rig. Set the float stop to the desired depth, quickly jerk the rod tip up, and let the line slack off. Repeat until your in. This works well along weed edges for smallies and over weeds for largemouths.
When smallmouths are schooled tightly and not biting, this is a good way to get something tempting in their faces. Sooner or later, one of them will breakdown.