So one of the problems I've been facing has been the planetary gears slipping out of alignment and popping out of place.

At this scale there's just not enough contact area between those two places to hold everything in place. It would probably work if it was machined out of metal, but with the inaccuracies inherent with 3D printing it's really no surprise my FDM machine couldn't do this.

So while this would probably work, I've decided to scale it from 1" up to 1 1/2", additionally we've adopted a "double herringbone" design that should increase the contact area and keep the planetary gears securely in place.

Once it finishes printing I'll be able to assess how well it works, I actually have forgotten to chamfer the overhang shown in the top set of gearing, but it seems to have came out well regardless! It's fixed in the files but I'm not stopping a 2 2/3 hour print to fix a chamfer that seems to have not been necessary :).