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I'd say just keep the weight off them and keep them out of the sun. No need to break them down.
The key thing is to keep them out of the weather. My 50 Dodge has tires that have been on it for 15 years and dont have any dry rot. The car is always inside though. A little bit a silicon based protectant wouldnt hurt. I dont use armorall because it is petrolium based and seems to speed up deteriation. BUt just clean and dry will work fine.
My shop is very dry....heated in winter, cooled in the summer.