Pastorp,
Living in Alaska as you do, might consider for your extra barrel for your Renegade a .54 cal instead of the .50. Been awhile since I messed around with the barrels of the TC`s , maybe that the barrel width of the .54 might not match the Renegade. I have a 12 ga New Englander but no rifle barrrel. Back in the 80`s I bought my two sons each a Renegade in the 50 Cal configuration. My oldest son, who also lives in Alaska, has shot two caribou with his.
Other than the different styles of the New Englander vs the Renegade I think both are comparable, although for rifle hunting I would choose the Renegade.
The .56 cal smoothbore, essentially a .28 ga, should be a lot of fun on grouse,ptarmigan, and ducks!!
Lot`s of luck and keep us posted on your experince with this setup!!