Prusa I3 spring loaded idler extruder

this is a derivative of Prusa I3 Extruder PG35l stepper with 24mm mount spacing (http://www.thingiverse.com/thing:81140).

The reason I made a derivative, is that the filament guide hole I was uncertain having it clamped between the idler and the main extruder body would work correctly, as I don't have my printer built to make these to try.
The 3d model of the springs I just got of a spring company so its up to you what springs to use, but for future reference if you have any issues with g