Can anyone help me with the correct tension on the idle bearing assembly on a Greg's Acccessible Extruder?

I can't get my filament to feed between the hobbed gear and the idler bearing which is spring tensioned. Everything else is OK and the extruder is not blocked.

What is the distance from underneath the heads of the screws that have the springs on them to where they enter the idler body?

Old Man Emu