I don't think it needs to be said again, but .280/.280 ai is the way to go. There is no comparison between a .280 and a 7-08, no matter the e barrel length. 7-08 is a little anemic. Not as bad as a .308, and has killed tons of big game, but If elk are on the menu go .280 all day. The straight .284 will give you more than the 7-08, the .280 will outpace the .284.

Nothing wrong with 7-08, but .280 gives you so much more and you already have the long action. 168's at 2900 fps is hard medine for anything. You would be lucky to get 2750 from a 7-08 with a similar length barrel. You would probably need to limit yourself to 140-150 g bullets with the 7-08 and a .260 will push a better 140g bullet with more authority than the 7-08.

Inside 200 yards, nothing you're shooting at will be able to tell a difference.