I'm in the process of getting my Rostock to begin its first print but I have been having issues with my extruder (you can read about it in my thread). This thread is about gathering information on bowden style extrusion particularly with smaller nozzles like a 0.25mm makergear hotend nozzle.
Using a smaller nozzle introduces bigger slack back problems in the bowden tube tha can be compesated by different retract lengths/speeds or perhaps a tighter PTFE bowden tube. I'd like to hear about other folks using bowden extruders with small nozzles, I want to know what retract lengths, and slic3r settings you are using as well as Marlin firmware tweaks to gain consistent extrusion with 0.25mm nozzles.
BTW I am using 1.75mm filament PLA plastic.