1. Black Powder revolver main springs cannot be successfully lightened. The spring weight gives positive ignition AND holds any cap debris in place on the nipple.
I thought this review of the 1858 Remington made by Uberti was interesting: Uberti/Remington 1858 New Model Army .44 Revolver
Specifically this part: The hammer draw is stiff due to a heavy (flat) mainspring. The trigger pull was a pleasant surprise, as it broke at about 3.25 pounds with commendable crispness right out of the box. I backed out the mainspring tension screw about a turn, which slightly eased the hammer draw and reduced the trigger pull to 3.0 pounds.
I'm not sure what it all means as I have to wait for my Uberti Remington 1858 to show up in the mail.