Discovering pull rates of all sets

I was just looking around to find a bit more information about pull rates as I’m planning to buy an Evolutions box and I came at this interesting piece of information: Cards of different rarities are always equally distributed among the six booster boxes in one case.

If I’m reading it correctly then you know the pull rates of Secret Rare, Ultra Rare, EX, Break and Holo of a certain set after observing the pull rates from a case, correct?

Now I understand that it is a lot harder to buy a case than to buy booster boxes, but if my above assumption is true then definitive pull rates should be all over the internet. Except, this isn’t the case, is there something I am missing?

Bonus question: What is the rarity of pulling a Common, Uncommon, Rare or Holo reverse foil card per pack? (I know there’s one in each pack, but asking about the ratio between C:UC:R:H)

Thanks in advance!