Very handsome guy you have there.. Love his dapples!
When it comes to mares for us we try to keep our mares the same height or taller than our stallion mainly because I personally do not like the tiny tiny mares and the stallion we are using is more of a stock horse type so I want mares that can compliment and accomodate him and his type.. I also look for mares that are broader built in the body because I feel the more body and width they have the easier it is going to be on them to accomodate their foal and have the room to get the baby situated and moved around come foaling time.. Of course JMO
I think you are very wise in looking for an experienced broodmare, that's the way I started out, I bought a mare that had had 4-5 previous foals.. Some things you want to look for and ask their owner about are things like:
*Does she breed easily? Has she had any breeding issues?
*Has she had any gestational problems? (ex: has she previously had issues with early fetal abortion, placentitis, late term abortion etc?)
*Is she an easy foaler? Does she need assistance or does she foal on her own?
*Is she a good mother? Attentive and potective of her foal(s)? (yes I have seen mares who have literally tried to take their foal's heads off :no: )
*Ask to see previous offspring whether it is in person (prefered if possible) or photographs as well as the stallion(s) she was crossed to for that offspring as it'll give you an idea of what she produces..
Of course this is all just my opinion.. I'm sure there will be others that will chime in and give tips and pointers too..
Also, with the face white your guy has, you might want to think about having him OLWS tested just to be safe.. The results pending the test will influence your decision on what mare(s) to cross him on as well..