What's the length of the bait? Could be you just need to come a little closer in length or diameter. Color could be key or maybe even the type of movement. In a hand pour it would be next to impossible to give you a head/tail one color and the body another. The best solution would be to order something in a jerkbait length (4 or 6 inch) that is close to the body color. Then order from Bass Pro Shops the spike it product or some other plastic lure dye, some guys even use Rit Dye, but doing that you would have to do a bunch with just the heads submerged. I'm not saying it can't be done. I'm sure I can match the body color very closely.
Could be a matter of too much bait, with no incentive for the bass to take your offerings. Let me know if I can help or if I can meet you sometime during a hatch to get a sample and take some casts
. Think about wacky rigging a 6 inch jerkbait, might be just the ticket. Wacky rigging would be to run a small circle hook through the center of the bait. Each time you jerk it forward, your pulling the center of the bait, when you stop it springs back out, it's a wacky way to fish. Some worms or catapillars have that type of movement and it can be a great way to rig a pencil type worm.