I tie my crayfish and other smallmouth "bottom bumping" patterns with a crappie sized tube jighead. I cut the forward section in front of the 90 degree angle off with a wire cutters to lighten the fly. (If you don't make sure you have a good warranty to replace your tip.) Then I flatten the remaining lead with a pliers. I dip the hook in jig paint and it blends in with the fly body.
If you get any of Dave Whitlock's materials (Books, DVD's etc.) on tying bass flies he uses a single mono tied over the bend on the hook as a weed guard. His placement of the mono is very specific and I've found works. I throw streamers into the root tangles of mangroves.
I very highly recommend checking it out.
I believe that any fish I've lost using Whitlock's weed guard are negated by the increase in strikes by being able to place the fly where the fish are.