Great post.I wouldn't want to leave them unposted for so long, myself. If they're not ready to be left down, then you're really just creating more work for yourself in the long run. And potentially allowing the cartilage to stiffen during that time so that you end up with a bend or curve in the ear that can never be fixed.
Are the trainers telling you that you coming to check her ears and post her is disruptive and distracting? Or are you assuming that? IME, it doesn't take very long to clean the ears and re-post. Maybe a half hour total to let the ears "air out," right? I would hope they're not training her so rigorously that she can't be spared for 30 minutes for you to check on her and re-post.
Also, I see that you're irritated with people offering their extended opinions on the board-and-train situation so, I'll preface this by saying - this is just my opinion so do with it what you will but, if I were paying someone to care for and train my dog, *I* still own that dog and I'm going to see them whenever I damn well please. I wouldn't trust someone who wants to restrict my access to my animal. If everything's on the up-and-up, then I should be able to show up unannounced and see the conditions in which my dog is being kept. I'm not saying I'd go storming in and interrupt a training session, but I would expect them to be able to present my dog to me in some form within minutes of me showing up. Whether that be bringing her out from her kennel to me, or taking me somewhere I could observe an in-progress training session without her being aware I'm there. And I would certainly expect I could spend 30 minutes out of a whole 24 hours of one day to re-post her...
I read your reasons for choosing a board-and-train option; those are just my thoughts on the expectations I would have if I were going that route.