I have never built a motorized mount. But I know people who have. From experiences of my friends I would say that a equatorial would be the way to go. It can move with one movement once aligned with "Polaris". Alt-Azimuth you need 2 movements for it to work. Equatorial platforms were basically designed for Dob type scopes. The scope sits on the platform while the platform moves. I have seen these and they seem complex for their purpose. If I gad a choice I would use a equatorial tripod or something similar.