OK, I made an offer and she accepted $1000 for him :) This is pending a vet check on Friday, where I'm going to have the opportunity to verify with the vet (whose wife is an endurance rider) that he's fit and built for endurance.
On the bridle thing, it turns out the breeder thought he'd had his wolf teeth pulled when he was gelded, but it had in fact been overlooked (probably because he was a cryptorchid so he had to undergo surgery). He's also got a few sharp points, so the vet is going to do his teeth and pull the wolf teeth Friday (at the breeder's cost). Overall, I feel like I'm getting a good deal here considering what I'm paying for him barely covers the cost of his gelding and having his teeth done this week!
On the second ride, I did indeed stay in the saddle a bit more, so I'm sure it will come with time - and a horse that's a little more relaxed in a "home environment" and "his person" rather than a stranger riding him in a round pen that was muddy and had a scary new tarp mound on the other side. Plus, I'm sure some of my apprehension over riding a horse I didn't know in less than ideal conditions where I didn't know the environment or the horse well enough to know what to expect. He did spook a few times (and who could blame him, their flock of geese chased me away yesterday!), but it was good to know what he felt like and did because it was not a big deal when he spooked and it didn't throw me off (literally or figuratively) at all.
I'm excited to bring Snickers home (how cute of a name is that?!). I'm not sure when that will be, though, because they're going to fix his bridle issue before I take him. From my understanding, they're going to wait until after the vet fixes his teeth before they try again. I'll post more pictures soon :)