Ken,
I own a Weatherby Mark IV Accumark UltraLightweight in .308 and it is a joy to carry afield. The first shot, which is of course the most important, is a tack driver paired with a Burris Black Diamond scope.
With that being said, I personally would not be shooting anything stouter than the .308 out of this type of lightweight model because of the light weight, recoil is stout. That's the compromise in these (and most lightweight rifles that I have shot) one obtains better ease of carrying through higher elevations, terrain, etc at the expense of recoil. I would opt for the 25-06.
My Weatherby has the factory 26" stainless whippy barrel too. When it heats up after that first shot, the pattern opens up. I ended up acquiring a Browning BLR in .308 a year later for a brush gun for deer in heavier brush while still maintaining the same cartridge. Of course it worked out okay but if I had to do it all over again, I would have found a shorter barrel and cartridge offering like the Ruger Scout etc. If you're shooting solely off of a elevated tripod, shouldn't be an issue but if you are planning on some other ground hunting, I'd definately opt for a shorter 22-24" barrel.
Good luck!
