Go with the 7mm mag. Better down range than the '06. 7mm Mag. maybe even more accurate but that's to be determined through extensive testing between the two carts. Maybe Shooting Times Mag. will take on that experiment.
Barrel length will make no difference whether 26" or 24". I own a Winchester M70 in 7mm mag with a 26" barrel and a Rem. M700 with a 24" barrel. I actually have the Rem. 700 being more accurate but will give the Winchester M70 (only 50 rds.shot so far)another chance as I need to shoot more rounds through it.[/align]