Howdy
I have no idea what the torque setting should be.
I doubt Uberti will be able to give you a number either.
Colts have the same problem, vibration tends to cause the screws to loosen.
With practice you will figure out how much torque to apply.
You just want to snug the screws up, you don't want to over tighten them.
It is not a bad idea to have a screw driver handy to snug up the screws every once in a while.
I have never used any thread locker of any sort on the screws of my Colts, I just snug them up a bit as needed.
By the way, Uberti screws are notoriously soft. Be sure to use a proper screwdriver with hollow ground bits that fit the screw slots tightly.
Uberti is also notorious for over torquing the heck out of their soft screws at the factory, so they will not vibrate loose. This makes things worse when you try to remove the screws the first time.
Standard hardware store screwdrivers have wedge shaped tips that tend to try to rise out of the screw slot as the screw is tightened.
Screw slots in soft Ubert screws are easily buggered up if a screwdriver tip rises up and climbs out of the screw slot.
This is my set of gunsmithing screwdrivers. Look closely and you will see the tips are not tapered, the business ends of the tips are parallel.