> 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...