Interesting, you didn't say how you made these, but there are low cost DIY injection molding machines that would work well for this. I'm envisioning a two step cast and mold process.
I have looked at non-lead pellets compared to lead pellets, and the ideal twist rates seemed to be much the same for the two. This is probably because the pellets I looked at were aerodynamically stable and thus less dependent on spin stabilisation.One thing which did stand out was that the non-lead pellets were much more affected by any pellet defects than lead pellets of an identical design. This would suggest that non-lead pellets need to be made to a greater degree of accuracy and consistency, and also are more critical of pellet barrel fit for good group sizes.If there is any interest, I could put the modelling results in a thread.