Laker, My 6.5-06 wears a SS 6x and I'd have no issues out to 700 yards despite chopping the barrel to 18" and suppressing it. Far more game is missed up close due to too much scope than game lost at long range due to too few x's. For $270 a pop on sale days, buy both and put the loser on a 223 or something. But if buying only 1, I'd go 6x.

The new 156 EOL and 147 ELD are both great options in the 6.5-06. Both perk nicely with RL26. Good luck.