Mike, you have received a lot of good advice here. Stocks do make a difference, but the technique of handling the recoil described by Snowman and others is important, too. What Texas Star says above should be absolutely obvious to anyone, but in "internet commando-land" it is not fashionable. The point is, find the stocks you like, refine your technique, and practice. It may not be possible for you to tolerate 100-rounds of 44 Magnums in an afternoon. If not, don't worry about it. It is more important to be able to fire 18- or 24-rounds that are carefully aimed and hit the target than to blaze away and do nothing but tear up the berm.

As to the 4- versus 6-inch barrel thing, I have never seen anyone seriously argue which is more comfortable to fire - it's the 6-inch gun. A lot of folks do seem to get along reasonably well with 4-inchers (I am not one of them) but the general rule has always been: 4-inch = "mean!", 6.5-inch = "better!", 8.375-inch = "almost tame."