I have made some two piece POP molds with the craw baits flat in each half, so I can hand pour one half, let it cool a bit, and then close, clamp, and inject the second color at around 340 degrees, so it bonds to the first half. I do the same with one piece open pour silicone molds. With the silicone molds, I pass my heat gun over the back of the second color, to get it to even out and bond better. It works well enough for me, but I'm just a hobby pourer.