(Incidentally, my mother was a tiiiiny bit upset when I initially dropped them out, because she had spent effort making sure all were in smoothly. I'm sure she got some glee out of my efforts to then get everything back in properly.)
Replacement post: Experiment-time!
First box:
First die: Didn't go in properly with 6/1 or 4/3. Went in smoothly with 5/2, no matter what rotation. Results were identical for each slot in the box.
I tried a lot of orientations for the first die for each slot, so I can confirm the box is fine, each slot appears identical.
Second die: 4/3 smoothly, other sides go bad, for each slot.
I did find 1 die that goes in smoothly no matter what, so at least 1 die is perfect. And with the other dice, some get stuck quicker so it appears there's a significant difference between the dice after all the sanding.
Second box: Some dice go in through 2 axes, but if I try them in the first box, only 1 works! In other words, the first box is a bit tighter than the second one. With the second set and second box, there were multiple axes for several dice, so I switched the sets and will now continue experimenting with the first box only...
Final testing results:
First set: Perfect/6/5/5/4/4
Second set: Perfect/6&5/6/5/5/5
So all in all I have 2 perfect dice, 1 near-perfect (in the second box it just takes a tiiiiny bit of force on the 4-3 axis, but in the first box it needs significant force), and a whole bunch that in the first box only have 1 good axis. I made my second box first set 6-5-4-3-2-1 and the first box second set 6-6-6-5-5-5 for display purposes.
