Please don't count this as expertise--just one season's experience with sweet potatoes. I planted some last year near the end of July (also downtown ABQ, morning sun) and by frost had a number of fingerlings. I just set an entire potato in the soil--the eyes had already sprouted, and the potato leafed out in a matter of days. Somewhere or other I've read that it's not a good idea to cut up a sweet potato and plant the eyes like you would a white potato--don't remember exactly why, but fungus or bacteria or rot or something like that played a part.

For what it's worth, the leaves of sweet potatoes are also edible--they taste a little "starchy," but they make a fine addition to a salad and are packed with vitamins. If you don't get actual potatoes, at least you can have some dark leafy greens! They're also lovely plants--worth growing on their own.