When I paint bismuth and use powder paint, I have to lower the temp, so I don't melt the bismuth. Other than that, I have no problem pouring lead-free. Some molds release the bismuth better than others. The ones I found that are easier to release are jigs with smooth surface and no features on their sides. Like a round head jig, Bullet bass, or football jig. The Poison Tail mold is troublesome, but I manage to get good pours.
I know there is a lot of debate about lead and lead-free jigs, but I try to accommodate everyone.