The reasons you listed (price, proximity and timing) are not things that make a breeder a great fit. The things that make a breeder a great fit are the dogs they produce, their goals for their breeding program, etc. You are looking for a lower-energy dog, I would start with finding breeders who produce the kind of dog you're looking for. GSD's are not a one-size-fits-all.
I would be VERY wary of the breeder not giving any sort of health guarantee. The fact that he charges up to $3500 from untitled parents is a little mind-bending. I can't comment on selling the small puppy (who the breeder still thinks is going to mature within the standard) for cheaper, but the whole thing smells very fishy to me. The fact that he takes deposits online is also off-putting. Any breeder I would want to deal with would want to get to know ME and if I would be a good fit first. I would pass.