I think Imold hit the nail on the head, I think the general rule of thumb is rings will usually tighten with 15-20 inch pounts and the base mount screws somewhere in the 25 to 30inch lb range, of course this can vary from one type of mount to the other.
As far as the Sun Optics adjustable mounts go I like the mounts for the most part its just unfortunate that they choose to use such chinsy screws.
For their airgun line of rings I used for the rings a 4mmx8mm metric button socket machine screw, I also replaced the base mount screws with M4-0.7x16mm socket(cap head style) and I also replaced the internal grub screws that interact with the gimbles(is it is the adjustable ones) with 4mmx10mm metric socket head set screws.
Two of these you will need to modify a bit, if you go with the button head then you will need to grind/mill down the outer edge of the head as it is a hair to wide for the recessed hole in the ring and it doesn't take much to get them to fit. For me I went with the button head as I liked the more flush look of that screw compared to the cap head which would stick out, if it doesn't matter to you then go with the cap head as it should fit fine.
The other is the gimble set screw, if you choose to replace them then you will need to grind the end to a point so the gimble can pivot on them. I found if while adjusting these screws that if you happend to have the gimbles move over to one side rather than more in the middle then it is possible for a set screw to be left with only a couple threads to grip in the base and be very easy to strip those aluminum threads with a steel screw, with a longer set screw that becomes less of an issue.
I realize this all sounds like a lot fiddling around for a set of rings but once you get past these issues they are a decent set of rings, not sure I would take them out banging around the woods hunting as I think a few good bumps could knock them out of alignment but for light duty backyard plinking and benchrest shooting and things of that sort they are fine.