Clutch return spring on Quicktime bellhousings

The spring on the bell housing is a very light spring. It keeps all the slope out of the linkage, prevents rattling and yes it will keep the throwout bearing from resting on clutch fingers. It does not have enough strength to return the pedal reliably if the clutch and over center spring are not there.

I drove my car for over a year without that spring because I was not aware that it was supposed to be there at the time.

I would say if you have removed the over center spring for a diaphragm clutch you will need a stronger spring than the stock one to ensure the pedal fully returns.