RE: 300 ultra Mag
9X @ 200 should be plenty considering that the military Snipers used 10X fixed out over 1000 yds for many years.
All Above are good suggestions. I would also say to take a look at the Nikon Buckmaster line. I had one on a Rem 700 PSS .308 and killed a few prairie dogs out over 700 yds. Granted mine was variable to 14X. Granted, not really needed, but I just like to bring critters in nice and close.
Good Luck