Theres no doubt that Held would be on your list, I believe Don produces more size in his progeny and not to sure if he was as hard as others such as Titus.. In regards to size, IMO believe that medium size and build would be more of a versatile working dog..
Size looks good and all, but also has the negative points, when we're talking Hips/ elbows..Especially when there tall dogs and heavy..