The best article I've read on the Chicles from a collecting perspective is Doug Spanning's article in Gridiron Greats, Vol. 8, Issue No. 25, 2009. It can be purchased via back order which is what I did since I wasn't a subscriber back then. Speaking of GG, I believe it was John Spano who did a 3-part series focused on player bios (this was more of a pro football history approach, but of course mentioned aspects of the set), and finally Jeff did a Chicle a Day thread:
Chicle-a-day
I still reference all of these resources to this day.
I can only speak to mid-grade collecting and I'm bad with dates, but around 4-6 years ago, I was picking them off in eBay auctions rather easily and building my set that way, but I noticed something odd that started a couple years ago. Auction prices realized started declining - not dramatically, but 10 dollars or so i.e. a nice PSA 4 low number may only hit around 60 in an auction rather than 70-80 just as an example. The response seemed to be no more auctions. Now I mostly just see BINs on eBay and having watched the auctions closely for several years, I rarely see a card at a BIN price that's tempting.
In terms of your specific questions on rarity i.e. ratio of low numbered cards to high number - 4:1???, print runs etc. Some of those questions I believe are unknowns, but the guys at MSB sports cards/BST auctions post here sometimes and they have some good data available and also post some chicles for sale - I think 4 or 5 of mine are from them.
One interesting thing I think Doug helped uncover is that it was probably believed the first 24 cards were issued and then the rarer group of 12 high numbers, but it actually looks like all 36 were printed in that second run (a reprinting of the first 24) - the details are in the article. And everyone always asks why there weren't more given what it says on the backs and the responses usually vary, but some think the cards simply weren't popular enough. Personally, given the number of players in the NFL, I suspect the number on the back was just an error. Had things been going well, I could see them issuing another 12 or something, but I don't think they had the knowledge to issue 200+ cards as a letter sold at auction recently showing they were relying on the teams to provide info and photos of their players.
When I started the set, Jeff was a big help answering my questions and posts often, so maybe he'll jump in too.
Hope this helps!