Vintage Bicycle Value is a tricky thing to determine plus the bicycles are two different sizes. Were I doing the buying, I would give greatest though to the one that was a decent fit for me. As for buying them both? Not a bad idea, if you can get a slightly better deal on each, and then sell the one that does not fit to help offset the costs of your purchase.
If you do get one, or the other, or both, you can figure out their vintage by applying the information contained in
How Old Is My Bike?