Welcome aboard. It's a fun place to be.
Be careful from whom you take advise though. The worst person here to listen to would be me.:o But I bet you'll read this anyway.
Elk really like to live. Though they have been taken with just about every cartridge made. I'd say that accuracy over rides FPE for sheep but accuracy and FPE are equals for elk.
Thus I recommend a 338 RUM for both uses even when back packing. They can be made as light as practicable and with the proper
brake, recoil can be kept to a minimum. Remember, the lighter the rifle the more effective the brake. Mine weights 10 pounds and I shoot it prone with no discomfort.
I had it at 12 pounds by adding lead to the stock then reduced it to 10 pounds by removing the lead. Recoil was better. My next modification will get it down to maybe 8+ pounds with no fear of recoill. I have a Holland QD brake on it. Defensive Edge makes a variety of breaks one of which could be selected for your specific need. Click here: Untitled Document
Bullet selection is good. It seems that most like the 225 Accubond and elk kills beyond 1K are common for that small group of shooters that are proficient out to that distance.
Personally I prefer the 300 SMK only because it shoots better than the rest in my rifle.
Recoil isn't a problem and barrel wear doesn't seem to be either. I've never heard of a 338 anything being shot out.
With one of the new nifty stocks weighting ounces and a light as practicable barrel and the proper scope and mount weight I'm betting you can end up with a backpack tolerable rifle. Remember, the bigger the bore the lighter the barrel.;)
This sounds like a great project. Keep us posted on your progress.