Model 1897 Mainspring Adjustment |Winchester Shotguns|Forum|Winchester Collector

I disassembled my 1897 and gave it a well needed cleaning.  I did not pay close attention to the position of mainspring tension screw.  Should it be turned down completely to seat or is it meant to be an adjustment?

I would also like to know what lubrication is effective for the action in this old gun.

Any help would be appreciated. 

Thanks