I think that the 6.5CM would be a decent choice.
If you are shooting a lot of rounds one right after the other, as you would in say, PRS, well bbl life will be less.
However, if you shoot as you say you do and let the bbl cool, well I can almost assure you that most quality bbl manufacturers will get substantially more rounds before accuracy degrades to a point where you have extremely poor accuracy.
Also, if you have a 1/4 moa gun that starts to shoot 1/2 after X amount of rounds, is that such a bad thing?
In the same way, if you load ammo too hot it will really take a toll on the throat of the bbl.
Well, just one man's opinion, good luck on your journey.