> You still need a prime tower when switching tool heads, but that is significantly less than a full purge. But I believe the INDX has the same restriction.

INDX no longer needs a tower. They say there is 13 milligrams of waste (which they call less than a grain of rice) on each filament change. So a print with 1,000 changes wastes 13 grams of filament. Details:

https://blog.prusa3d.com/prusa-core-one-indx-orders-now-open...

I'd kind of considered printing a rather small thing (seriously, 3x3x3 cm or so) in grey using this technique (using white and black filament). It told me it'd require 140 (== number of layers) filament changes and it'd take 5 hours. (In fairness, if I wanted to print 10 at once it'd probably take a similar time.)

So... honestly it's kinda silly IMO. If I wanted to mix colors in a hacky way I'd just... wait, hold my beer.