Running an all metal hotend on an Ender 3 (first version), and I've found my optimum retraction to be between .75mm and 1mm, depending on the filament I'm using. The Creality Cloud slicer won't allow under 3mm retraction, which causes the filament to begin sticking in the heat break. My current default is to turn off the retraction, otherwise I get layer separation and areas of severe underextrusion until the extruder can force the filament back into the hot zone. Creality Cloud slicer should allow retraction down to .5mm so those of us with modified machines don't have to choose between stringing and getting the filament stuck in the heat break. There's a few other settings I'd like to see made available, but the retraction distance is the biggest one for now. OK, I'm done being whiny for now. 😆