The newspaper cups work way better then I thought they would. They hold moisture really well and are more sturdy then I would have through. I am actually a little worried about how well they will decompose. We also like that you can, more or less, pick your pot size. Anyway, now that I know they work. I am going to put the design for the seed cup mold up on Thingiverse for free download. Should be up this week. Not that it was complicated, but it will save you some time working out the right dimensions.
Kids designed and made their own drop spindles today. Even my wife made one up. You can adjust the weight and density so really do nice job.