I only own a 5" 629-3 Classic, so I can only speak from that experience with N-frames, but I've noticed many more comments over the years about 5" being the best all-around barrel length for N-frames. For the range, if you can find a 5-incher, it ought to serve you better than the shorter barrel, even though 4-inches would work, too. Either way, an N-frame is a big hunk of steel.

I like the fiber optic sight. Where'd you get it?