I'm working on the extruder right now, one of my goals is to keep it within the face profile of a standard nema 17 (42x42mm). This of course comes with some space issues as I'm trying to make it geared. I'm considering making one gear stick out slightly as a sort of thumbwheel for manual extrusion/retraction to help with loading and unloading filament, any thoughts?

Anyways, my current dilemma is how much of a gear reduction should I use? I'm wanting it to be usable with the pancake 20mm nema 17s, and I have two reduction ratios right now, a 1.8:1 and a 3.06:1. The E3D titan which people use with the stepper's I plan to use has a 3:1 ratio, is this "just right" or does it provide unnecessary torque? Would 2:1 or even direct drive work? I'm asking mostly for higher print speeds upwards of 100mm/s.