Nice video! We might go into making cored toys or sheaths at some point, but we will likely be looking into different methods - the precision of a coin filled tube might not be up to snuff if you hope for a 15% failure rate or less.
For something more ergonomic, do you think it would work to use another positive 3D model or sculpt instead of a pipe, and perhaps hold it in place by other means than just gravity - could be a dedicated holder attached to the mold, that the core or sheath positive screws into or attaches to in a more precise fashion?

Also, we'd love to see an actual video of you pouring marbles and fades with a cut to the outcome - sometimes graphic visualizations aren't quite enough to understand how a concept works :)

Keep up the dildonics :}

If you have some kind of drill press or ring stand, that'd work perfectly. I have barely any tools here, so I've gotta stick with what I've got.

As for actual videos of the process, that's a bit tough. I don't make many toys anymore, only very occasionally, so I don't really have anything to show. Sorry!

Aw that's quite alright! We'll apply some R&D ourselves!
The ring stand was what we were considering It might work!