If you are serious about registered stock, the selection of sire and dams is extremely important. Researching genetics, show records, appraisals, and milk records if applicable all play a part in planning your herd.
What the current sire and dam "look like" gives you just a small snapshot. I would pass on a small doe, she may have some health issues that inhibited growth.
I would also go with tested herds that can show proof of being disease free.