In becoming a mother through donor insemination. What kind of a donor should I seek?

Personal choice. I'd only consider donor sperm from a registered us sperm bank, they have protocols to protect from risks of transmissible disease. The choices are really 100% personal, not medical. Hair color, eye color, height, weight, race, ethnic origin, education - which ones are important to you? When using relatives, friends, or internet donors it's much more complicated.