Re: buying a starter gun
The .260 has great ballistics and light recoil. However, understand that there is little in the way of factory match quality ammo available in .260 so you're almost required to reload. Also, good .260 brass is much harder to find (at least for a novice) than .308 brass. I'd bet nearly every great shooter here has a .308 in their safe, so don't overlook it based on ballistics alone. The .260 is the shit today, but something better may come along in a few years which pushes the .260 out of favor. People have been shooting the .308 for 50 years and it will still popular 50 years from now.
That said, it sounds like you have a decent setup in mind. The .260 is awesome and I don’t mean to try to talk you out of it. If I was starting over today I’d probably opt for a 6.5 of some sort. There are some drawbacks with the .260, but as long as you reload and obtain/make good brass, you’ll be good to go.