Re: Jem BSB cant lower the strings any further
Well the studs do screw down into the threaded metal "sockets" (unsure of the proper term) which are set into the body. However, from taking them apart on several guitars it has been my experience that when they are bottomed out it is not due to the stud being at the bottom of the shaft, but because the flanged head (into which the trem's knife edges fit) is flush against the top of the body. Yours may be different but that was the case with my 7VSBL.
Regardless, there are other factors to consider. If you were to modify the studs as you suggested, you would be sinking the trem deeper into its cavity... Are you going to run into problems there? In other words, if you trem is that low in the trem cavity, will you still have a full range of motion without hitting or rubbing the body? Also, as you sink the trem your action does lower, but so does the angle of the strings relative to the neck. If you get a very low action using the method you suggested, without a neck shim, it sounds as though you may have moved the trem out of its relatively parallel string position and as a result may run into significant fret buzz issues.
Again... I'm not a pro tech but these are the things I have run into in my experience that might be worth considering...