a lot of talking about buying and zero on selling. All your money is made in selling and that's, by far, the hardest part of the equation. Who cares if something appreciated 200% in theory if you can't sell it anywhere near that price. so the first question is...have you sold anything before and at what scale?
also as the value goes up all the risks associated with the whole process goes up as well. based on your questions, you seem risk averse. A key problem with jumping into retired sets is that A. You can't be sure the product is 100% legit...the more you mitigate this risk the more you pay. Whereas with current sets you can be relatively sure it's legit if its from a major retailer.