The Sendero is a good platform to start with for LR hunting and range work. Not sure of the rifle golf but it has to beat regular golf if you get to involve a rifle! I like the 7mmRemMag, I have other rifles in .300WinMag and .243Win, but the Seven is my GoTo rifle everytime. I do not have any experience with, and therefore can not comment on, Sako products. Hopefully, whichever one you choose, you'll get a dandy and it will be a pleasant experience.
As for the glass magnification, I guess it's a personal comfort thing. Some folks have better vision than others. My eyes aren't the best and I prefer the 6-18's and 6.5-20 power range of scopes, especially for range work, load development and varmint hunting.