I personally don't feel your mare has enough desireable traits for breeding but if you are set on breeding, from the studs you posted, I like the first and the last, although the first one looks very thin and has no muscle tone.
Are these registered horses?
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I'm not trying to rail on you, but it has always been my opinion that it's better to save a horse for your next trail buddy than it is to breed for one.
Breed if you want a top dollar show pony. But there are many yearling TWH out there who are being run through the auctions, starving, and begging for someone to save them from their misery. I think any one of them would love to come live with you and be your next best friend.
I might also point out that breeding in July or August like you have planned is not a good idea. Your youngstock will be significantly smaller than what is already bred this season. Plus being born in the hotter months of the year can cause some complications for mom and baby, especially since you live in the south. Your mare is already 19, underweight, and could face some serious issues being heavily pregnant in the summer - such as tying up. June is pretty much the last month for breeding season, and even that is pretty late.
I agree that you might as well just close your eyes and pick. Either way you're putting your mare and a foal in danger. She's not in good shape and you must think fairly lowly of her to put her in that danger for YOUR happiness. A $250 stud fee is just...I can't even fathom doing that to my mare. Sorry to be frank about it, but you're making very, very poor decisions.