Re: 7mm RUM loading advise.
I've got a left handed LSS 7RUM myself! I haven't had the chance to work with it a whole lot. I've been shooting 150 gr Ballistic Tips at 3400 fps. The recoil from the bench unbraked is fairly sharp. A brake should tame this round nicely. I just got a Limbsaver recoil pad for mine, and that is probably all it needs.
The other guys should be able to give you more info on the other stuff.
Good luck and good shooting!
Lefties are the only ones in their right minds!
(and I ain't talkin' politics!)
NRA Life Member