I purchased a nickel plated square butt model 36 while I was in the USAF in 1965. Serial # 392437. I traded it off when my fellow police officers made fun of it for being a “pimp gun” I should have kept it.
My father in law served in Europe during WW 2. He would not talk about his experiences there. He brought back a small 25 caliber pistol that he took off of a nazi soldier. In his later years he had an interest in the civil war. He built several pistols and a rifle from kits that were for sale...
You should be able to find a YouTube video on how to tear down your 66. Use a gunsmith specific screwdriver to remove the screws. I use spray carb. cleaner. Ballistol works well for lubrication.
As I understand it the term means that when the revolver is cocked in single action it should not be possible to push the hammer and have it fall. If it does there is a serious problem Parts will have to be replaced by a qualified gunsmith.
I would suggest that you look on YouTube for videos on how to disassemble and clean/lubricate your model 60.The weapon is over fifty years old. It probably has dried up oil. Get a good set of gunsmith screwdrivers so that you won’t bugger up the screw heads is very important.
If you stay with 158 grain 357 rounds you shouldn’t have any problems with a cracked forcing cone. The 125 grain rounds were the ones causing damage to the forcing cone.