AS a second gun or third gun , I would not have one.
So, your third gun is.......Desert Eagle .50AE?
Yeah, I agree with you about normal carry as a primary or even second gun should be a service caliber. But, I have the little NAAs for the abnormal. I always have my .22 in my left pocket/weak side pocket. I usually carry either a 9 or an ultralite .38 in the strong side pocket. Then, occasionally, if I deem it prudent, I'll wear a long, baggy Hawaiian type shirt or in cooler weather when I can, I'll wear a long vest as a cover garment and wear a belt gun. When I wear a belt gun, much of the time lately I carry my 3" Taurus 66 .357 magnum in a JIT slide with a Taurus 85UL in the strong pocket as back up. That way I can carry two speed strips loaded with .38 158 +P which will reload either gun. Now, that's when I'm paranoid.
I run a paper route twice a week and collect once a week and have enough money on me then that I do get kinda paranoid. I'll usually carry a belt gun if I'm going to a big city, too. I occasionally go with the 9 in a pocket and my .45 in a summer special, but I really like that .357 and the OWB belt slide, comfy and compact.
In the above cases, I always have a NAA .22 in my weak side pocket. It's better than not carrying it and I figure if I'm struggling with someone and only have my weak arm free, I can screw that thing in his ear and let him have it. You can't tell me a .22LR, much less a magnum, to the head point blank ain't gonna hurt.
I mean, I'm no gun writer, but I have killed a lot of things with .22s, even pistols. They will do more'n you think or seem to give 'em credit for. I know I don't wanna get shot in the ear with a .22 mini, LR or magnum.
I do have the little super companion as a primary option when nothing bigger will do. I do not wish to be unarmed and there are times when it is that or being unarmed, few, but there are times. Besides, I had run out of things to buy and thought it'd be cool and fill a niche.