This is a really clever setup! The end effect is great, and I like that there are even additional improvements as you mentioned at the end. Thanks for taking the time to share it!
Slot Color view (alt + C) can be a lot easier for choosing colors. Saves you two clicks: one to open the dialog, and one to hit OK.
Another tip, you can type
+ and then a number into the translate, rotation, etc text boxes, then hit enter and it'll add that much to whatever the original value was. To subtract you still need to start with
+, but then put a negative number, like
+-123. You can also start with
/ for multiply and divide. However, I believe it only works when selecting a single bone. We should improve that!
Instead of moving each bone, it may be easier to use scale. Select all the bones, then set the scale X to eg 0.8. Since the bones are nested in the bone hierarchy, the first bone will be 80%, the second bone will be 80% multiplied by it's own scale of 80%, etc. So you get increasingly smaller bones: