Lupo has it right. I would add that a good float rod should be at east 10 1/2 feet long, and that the very best float and jig angler I know, Nick Amato often runs his jigs as much as three to four feet off the bottom. The fish w WILL come up for a jig, so don't try so hard to be right near the bottom. Also consider what Dave Vedder describes in his book. Rig an inline slinky under the float. Make a normal slinky and attach a swivel to each end. Tie the mainline to one swivel and the leader to the other. This keeps the float perfectly upright unless you have drag from line or are dragging the bottom. Another advantage is that you can premake slinkeys that you know are weighted just right for the float and jig you plan to use.

Also consider that many baits and lures besides jigs are deadly under floats. Eggs fish really well under a float as do sand shrimp.

When fishing bait its okay to occasionally drag bottom. Many top float fishers purposely drag bottom with bait and some lures other than jigs.