I have to go with Model520Fan over Saxon Pig on this.
I carry a handgun with me pretty well all of the time since I became a cop more than 30 years ago. For much of the first half of my career, my primary plain clothes/off duty gun was a 3 inch Model 66. Fish AND fowl, I guess. Round butt frame but adjustable sights.
The superiority of the adjustable sights, with the bigger, blockier sight picture they provide, is a huge advantage for any kind of sighted fire that must be rushed along. Using your sights properly is what gets you hits, which are the point of the shots being fired in the first place
I have never seen how adjustable sights can negatively impact a carry gun that isn't just loosely thrown into a pocket. When using a proper holster, as one probably should do for a handgun the size of a K frame S&W or a D frame Colt, the sights are incredibly unlikley to get hung up on anything during a draw stroke. My department shoots 3 or 4 times a year, 400 or more armed, and I have NEVER ONCE seen an adjustable sight gun get snagged on anything during draw stroke.
Once the gun is gripped, drawn and presented towards the threat/target, at THAT point the bigger, brighter adjustable sights are easily seen and lined up on target so much faster than can be done with the typically, smaller and darker sights most fixed sight guns use.
The square butt gun tempts the shooter to buy large 'target' stocks, but they are often too large to help. and can be a small bit more difficult to carry concealed, but if the stocks are otherwise similar, say, both being checkered Magna stocks on both round and suare butt guns, one cn be hidden away almost as easily one versus another.
My department (the Salt Lake County (Utah) Sheriff Office issued the Model 15 and pre-15 in both 4 inch and 2 inch square butt and 2 inch format from the early 1950's until we began issuing semiauto pistols in 1991. Deputies could also provide their own Colt, S&W or Ruger 6shot .38 Special or .357 Magnum handgun if they preferred such. We could carry Magnum ammo if we could qualify with it. Most detectives wanted the 2 inch gun but the good shooters preferred the 4 inch gun. Anybody could conceal the longer square butt gun as well as the shorter round butt gun if they used proper belts (more important than many believe) and holsters and dressed accordingly.
I did find that over the years, the deputies qualifying with the adjustable sighted guns shot higher scores consistently better than the deputies that had chosen or bought fixed sight guns. Their good shots were rung up faster, as well.
Saxon Pig, a good experience for you would to acquire a 2 inch Model 15 and a 2 inch Model 10 or 64. Fit them with whatever slender stocks you can find, such as smooth Magnas, and actually carry them concealed for a year, one week the square butt adjustable sight gun, the next week the round butt fixed sight gun. Use the same quality of design and materials on your belts and holsters, and keep track of how ofter your concealed guns are pointed out to you by others. Then shoot some fast, draw-and-fire drills from concealment, with someone timing them. You will find, if you rush fast enough to simulate you are taking fire from bad people, that you will get better hits with the adjustable sight guns, and unless you dress really oddly, they won't snag on stuff and halt or slow your draws at all. Shoot at meaningful distances, 7, 15 and 25 yards.
You will find a valid reason for big blocky adjustable sights on your concealed combat revolver; you will hit things a lot better.
That is what my department learned, among other things.
