I used to own a 4" Xframe SW in .500 magnum. I loaded the Sierra 350gr JHP over 40 some grains of H-110, 42.5ish I think was about all I could control with a bunch of practice.
Once I shot diagonally through a 2x6 with it, about 9" of hole drilled in the wood, half inch entry wound and half inch exit wound in the board.
I will point out that I have not seen a bear in the wild in Alaska since I earned my residency and bought a grizzly tag.
In interior Alaska, north of the Alaska range and south of the Brooks range, bears tend to max out at "about" six feet square and are pretty gun adverse by the time they reach that size. For the interior, where I live, the old saw about "44 magnum or better" is still true, .44 magnum is plenty.
2 other problems. One, H-110 doesn't like to light real easy in cold weather, especially between about zero dF and 32df. Lil Gun works just fine at those temps if you like it.
Second, an X frame is a heaping handful of steel, very hard to get it out of the holster and pointed in the correct direction promptly.
One of my hunting buddies got me going doing failure drills, you start with a holstered sidearm and deliver a rapid controlled pair to the chest and then a carefully aimed shot to the brain box of your target, total time is starting beep to third report. At ten feet I was quicker with a folded knife in my pocket and charging the target than I was with my X frame.
I know there are plenty of twenty something year olds fresh back from the sandbox who can draw an X frame faster than me. 20-30 years from now their rotator cuffs are going to be as tenuous as mine are today. An Nframe sized .44 or similar (Redhawk) is going to be lighter enough to be much faster out of the holster for that all important first shot.
At the coasts, white bear to the north and salmon fed browns and blacks to the south, guides routinely carry rifles, 45-70 and up.
As a hunter I am fine with a 4" barreled revolver on my hip. If I were a big time fisherman in bear country I would look carefully at the Super redhawk Alaskan with a good quality chest holster that would work well with hip waders.
For Montana ( no offense) I'd load up my .45 Colt Redhawk pretty stout and not worry about it. I would not feel undergunned with a RCBS 270gr SAA Keith style bullet at about BHN 15 loaded to mmm, 20k to 25l psi, should give 1100, maybe 1200fps with any of several different powders.
The SW mountain guns should be able to handle limited quantities of at least some of those loads as well, and pack easier and draw faster. I think the 629 is 44 magnum and the 625 is 45 Colt.
I would encourage you to read up on John Linebaugh's website before you plunk down serious coin,
http://www.customsixguns.com/writings.htm