Like said , whichever rifle you shoot best and have the most and best data and experience with. The 270 has a solid edge at distance tho. But did the guide really say most shots inside 100 yards?
Bipods, I highly recommend a spartan precision with a flush gunsmith adapter. Handy in vest pocket but out of the way for still hunting and super light. And bring trekking poles but experiment with them and looping the handle to use as shooting sticks.
Also, run some drills , timing yourself , to go: from hiking with pack, gun on sling or however you hunt, to getting two accurate shots off at just 100 yards..in prone position, prone over pack , seated over top of pack.
The first time thru the drill will likely be EXTREMELY eye opening at how much fumbling with buckles and slings and rangefinders happens.
Start time at go, remove pack,do things, shoot , stop time.
I run this with a 22 also once in a while for a humbling experience.