I've OFAed 3 dogs. The first one was able to be done without sedation, but we trained for being restrained on her back.
The second two were sedated. My big male shepherd there is NO way they would have gotten those X Rays unless he was out. For that matter the lab is just a wiggly little worm too, so almost no chance there either but for a different reason.
I don't love sedating my dogs either... but they've all been okay.
If you have the type of dog that could learn to be restrained that way and cooperate, and you have access to a vet who will do it without sedation, then all you have to lose is money if the positioning doesn't look good once it's done.