Why your guides recommend a 375 is eye opening, a 338 with a stout 250gr pill is ample on big bears, anyway I digress.
My own 375, a Weatherby version, is on a Win Model 70 Classic Stainless that I rechambered the factory barrel from H&H to the above.
Mine wears a Bushnell Elite 2-7x32 scope and is sighted for 3" high @ 100mtr with Woodleigh 300gr PP's. My load runs 2830fps +/- out of my 24" barrel and will clover at 100mtrs.
My rifle is in a HS Precision Classic Sporter stock with the Uncle Mikes recoil pad, wish it came with a Decellorater, but alas it didn't.
Off a bench recoil is stout but manageable, it feels harsher than my custom 416 Rigby that has a Decellorater on it.
If longer shots are on the cards, a good fast load in my rifle with a 260gr Accubond @ 3000fps really shoots flat, it is almost as flat as a 30-06 180gr load, and knocks stuff flat, even our huge water buff here.
I use this load on deer here and it is surprisingly flat shooting.
The 375 Ruger is only slightly behind my 375 Weatherby in velocity and is a good choice, however I like the Weatherby version a whole heap more.
Hope this helps you decide.
Cheers.