I think I read about the first 10 words of each reply, and all of them were headed in the directions of monsterous recoil, deafening muzzle blast, and inefficient burn.
So, yes Ballistics By the Inch did a fair job on testing in a sealed tube. 95% (guess) of the .357 guns in the real world are not sealed tubes. The only ones that are are lever rifles, the few bolt rifles, the single shots, and Coonan 1911s. You get a significant drop in velocity when you add an unsealed port of any type, and a cylinder gap is one. The varying degree of loss depends on the amount of cylinder gap.
A 357 snub is a potent defense weapon. It is compact and powerful, typically has 5 shot capacity although there have been a few 6 shot snubs over the years which met the market with less success than the smaller framed 5 shot guns. I have seen barrels as short as 1.8 inches and I happen to own the longest barrel I have ever seen which is 15". The 357 was intended for the 4 and 6 inch barrels commonly found on "duty sized" revolvers, but can be made to excel just as well in a pocket sized gun. Balancing concealability with function and power pushes me towards something in the 3 inch range. Shorter than 3 inches in a magnum revolver does not give time for most powders to burn snd you end up with the large flash and loud report that people often pound on when talking about 357 and concealed carry. Longer than 3 inches becomes harder to conceal comfortably, and barrel length adds weight. So for a good 357 defense gun 3" gets you enough barrel to reasonably shoot most powders and/or factory loads, you still have a concealable gun, and you are avoiding a good chunk of the muzzle flash and blast associated with most short barreled guns. Like all things, what is best is subjective, but for me the shortest 357 I would buy for defense is a 3". I would try to find it in a k frame sized gun for the 6th shot.