Greg....you're referring to the color with red flake?
You might try the pumpkin X2 colorant but use way less to start, maybe 3 to 4 drops in 4 ounces or increase the drop count proportionally to the plastic volume. MF makes a chartreuse pumpkin, no.#56, that may be just slightly closer. If you have a pumpkin colorant and its too brown you might try adding a green as long as its not a real bright green and even then just a drop or two to start and see if it goes in a direction the will get you close.