I have an example of one with the 'universal mount' - it requires adding a least one screw hole on anything you would mount it on. They are a very simple design, the windage is set by loosening the lower knurled nut and sliding it, no clicks or even tension on it; the lines are not marked so you have to be careful when loosening it so it doesn't move or you basically start all over. Elevation is set by turning the post in or out - it's just a threaded round, you line it up just by 'eye'. The parts look well made even thought they are really basic, I still would suggest spending more for something else.
The sight disk has a very small thread, the hole is also small and I think to drill it out much would weaken it to much or even break through.