Re: Which 7mm on which Savage?
I would start with the Savage 111 Long Range Hunter in a .25-'06 chambering, which is an OK chambering for a switch-barrel. Not my first choice from a bore longevity standpoint, but not bad overall for a factory chambering, either.
This rifle also provides the proper bolt face diameter, magazine configuration, and action length for my next suggestion.
I would then obtain a similar countour, longish barrel chambered in .280 Rem, which is a sufficiently well established chambering that wildcat-related issues should not crop up too harshly. Built on a military cartridge case, feeding has not been an issue.
I seriously doubt that a muzzle brake would be really necessary with either chambering, and I use Limbsaver Slip-On recoil pads, as much for their additional LOP as for any real recoil issues.
I could even see myself doing this build, and getting an additional barrel chambered in .30-'06, too. For that, I might be persuaded to go for a brake.
For your build, I would do nothing beyond obtaining the second barrel. The rest is good to go for the things you have in mind.
The .280 Rem/7mm Rem Express has very good performance, puts the .30-'06's case capacity to use at just about its very best efficiency, and does it with lighter weight, lighter recoilling bullets having very adequate BC values.
For factory ammo, the Hornady 139gr SST Superformance hunting load is very respectable, and has what I believe is very capable performance at, or close to, 1000yd out of the right barrel length.
Handloading; one need look no further than the Nosler 120gr and 150gr 7mm Ballistic tips, and/or similar Partition offerings. There are acceptible Nosler 7mm offerings in 120, 140, 150, 160, and 175gr in Ballistic Tip, Ballistic Silvertip Combined Technology, Accubond, and Partition constructions. Covers the full gamut, I'd say.
For lesser demands, the case can be downloaded quite effectively. In a pinch, it could even be a downright 'Ungodly Hammer' of a Varmint rifle.
I'm 65; am not the most hippity hoppin' frog in the pond, and have recently forsaken the prone for the bench. I own a pair of .280's.
Greg