tidalwav90 is correct. The preferred way to handle these is to do as much research as possible and then submit a mostly complete checklist. Like the Rediscover Topps buybacks, Topps doesn't really release a comprehensive checklist for these sets. Using COMC, eBay (sold and currently listed), and Worthpoint.com (you don't need an account to view searches on Worthpoint), a good portion of cards can be discovered, but it would be silly to expect every card to be discovered before we listed the checklist, simply because there's just no way of knowing.
Once a good base checklist has been established, if another card is discovered down the road, it's a matter of adding one card. Adding one card is much easier than individually adding 20-25 cards down the road.
So, do as much research as possible the sites mentioned above, as well as any others you might know of, compile as much of a checklist as you can, and submit it like any other set.
I'll never quit collecting entirely, but I am downsizing. Check out my COMC store and help me thin out what I don't want so I can buy cards that I do want. See something you like? Send me a message on here, and we can knock the price down quite a bit. I'll even take a bit of a loss if it means getting you a card you really want.