Racingsnake, I've followed some of your posts, and also understand some of the limitations in terms of access to firearms (South Africa if I remember right from a previous post, but I may be getting posts confused.)
Of the two you provide, I would go for the mouse gun in a .32, but not sure if I'd go much below that. I'd hesitate on a .25 without good quality ammo.
Falcon had a really great answer, and I'd echo most of his sentiments.
Although I would counter with the following: Does this have to be an eother/or question? Are you legally allowed to carry both? This might be the most comprehensive solution.