RE: .308 win. or 30-06 Long Range
Out of the 2, I'd take the 30-06 if you handload, .308 if you don't.
There isn't any difference in accuracy if both are loaded to their potential, the 30-06 would have an edge at longer distances because you could use heavier bullets.
If you are having something custom built, the 6.5x284 is better than either of them.