Hey Ric,
I bought the same mounts I always do, the Accushot high profile 1 piece mount. CDT is correct when he told you that the newer high mount model now has 3 clamping screws instead of the 4 found on the old models, but they have held just as well for me. The medium height mounts don't work so well for me, I really prefer a higher mount I just find them much more comfortable and conducive to quick target acquisition.
Regarding the mounts you received,,,,, are you sure they sent you the medium height mounts? I was not aware that the medium mounts now have 3 clamping screws, I thought they still had 4.
Anway, like I said, I have a couple of the newer 3 clamping screws mounts on several rifles and they've held just fine. Just make sure you clean all the surfaces (mount and rifle), including the clamping screw threads, with denatured alcohol prior to installation and be sure to use the Blue loc-tite and let it set for 24 hours before firing. You shouldn't have any problems. I also put a drop of the loc-tite where the mount base grips the dovetail slots or the raised scope rail.
As for this forum being such a nice place to hang,,,, you are absolutely correct on that count !! Fantastic bunch of people without a doubt. I spend as much time as I can spare on this forum and it provides me with much enjoyment.
Take care, good shooting.
Jeff