Alternative Nozzle Fan Duct for Prusa MK3 R3 (better cooling)

This design uses two concentrated air currents that meet behind the nozzle. This works very well. (see the picture before/after the change. I've used https://www.thingiverse.com/thing:3302357 for the test).

To my own surprise this design doesn't weaken the cooling in front of the nozzle. Maybe there are strong turbulences or this is the result of the venturi effect (https://en.wikipedia.org/wiki/Venturi_effect).

Unfortunately Prusa released a new version (R4) of the extruder, this makes th