Manual says tighten as much as you can by hand with the appropriate small allen key. The allen key will bend so there is only so much torque you can apply. So don't use a torque screwdriver. But I guess maybe around 10 inch lbs. considering the size of them. I read here on the forum that they are using 2 different sizes, the later ones using a slightly smaller metric size (I think 2 mm but not sure). Also, the manual is online. It says this:
Remove the gas block set screws using a 3/32” Allen Key. Once the screws
are removed, remove the gas block, piston, and piston rod from the
assembly. Apply medium strength threadlocker (blue) to the gas block set
screws when re-installing and tighten firmly