I have also considered changing to 1,75mm filament, as the 3mm filament ABS does not extrude well through a 0,3mm nozzle (this in the quest for higher quality prints). The standard extruder may not work on 1,75mm Filaflex, but what about ABS? Is it worth a try?
The problem as appears to be that extruding 3mm down to 0,3mm is an area reduction of 100:1, whereas 1,75mm to 0,3mm is 34:1, which should make it much easier on the hobbed bolt, no?
Best wishes to all for 2015,
Wally