The Smith (Little torch) is a great torch.
For doing guards the watchword is low heat. You don't need, or really want, a flame anywhere as big as a plumbers torch. You only need to heat the metal evenly and to about 400F. Many use an electric heat gun with great success.
The biggest causes of bad solder jobs are too much heat ( applied to the joint directly, and thus burning the flux.) and too much solder. A tight fitting joint, absolutely clean metal, the proper flux, gentle heat, and just a tiny application of solder after the metal comes up to the right temperature will assure a clean and complete joint.
Stacy