Philthygeezer...
IMO the 7mm Rem Mag is one of the premier long range hunting firearms. I personally would go with the 26" bbl. for the extra velocity. I had a 26" Ruger #1 in 7 mm Mag and it was really a long range hit'em hard and put'em down firearm. Im now shooting a 24" barreled Sako in 7mm Rem. Mag. Its a great and accurate gun, but no easier to carry and handle than the longer barreled single shot. Youve got the opportunity with the Encore to have the best of all worlds, long barrel for performance and still in an easy-to-handle-package. This is one caliber I have always owned and hunted with since 1970.
If you decide on the 24" barrel then I think you should be looking at the .280. Less power (slightly), less recoil, and no reason to be stretching the performance envelope.
In truth, and in the field there wouldn't be a big difference, but if you go with the 7mm mag, go all the way!
Silvertp