Adjustable mounts for springers. Yes or No?

1) Are they made for springers? 

2) Are they beneficial to/for a 
springer? 

3) On a TX/Prosport platform 
would they be recommended? 

4) On a magnum platform, would 
they be recommended? 

5) Do they hold consistently 
and precisely on the platforms 
above in #3 & #4? 

6) One piece or two piece mounts? 

7) What brand/manufacturer you 
suggest? 

Lastly I have a bkl 1-pc mount w/droop comp. Like an idiot, I stripped 1 screw that's on the end. So it could be the 1st or 6th screw. I am wondering that since I don't have a tap/die set, will those other 5 screws hold almost as well? On a magnum spring gun?