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Goals:

* A 2 : 1 ratio of 4E : CH
* A 3 : 2 : 1 ratio of common : uncommon : rare (or 3:2 C:U if no R)

"CH uncommons" includes all C1 and U3 cards.
"CH commons"   includes all C2 and C3 cards.

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Uncommons and commons only:

There are 121 4E commons, and 121 4E uncommons.
There are  37 CH commons, and  30 CH uncommons.

There are 242 4E cards, and 67 CH cards, which is closer to 7 : 2 than 2 : 1.

A 2:1 C:U ratio gives:

242 4E commons, 121 4E uncommons, 363 4E total
 74 CH commons,  30 CH uncommons, 104 CH  total

So that's around 3.5 : 1 for the 4E : CH ratio, not quite there.

Doing 2:1 for 4E and 2:2 for CH gives:

242 4E commons, 121 4E uncommons, 363 4E total
 74 CH commons,  60 CH uncommons, 134 CH total

That makes the 4E : CH ratio for Commons 3.27 : 1,
but the ratio for Uncommons is 2 : 1,
and the overall ratio is 7.2 : 1,
so that's just worse.

Doing 2:1 for 4E and 3:2 for CH gives:

242 4E commons, 121 4E uncommons, 363 4E total
111 CH commons,  60 CH uncommons, 171 CH  total

That gives about a 2 : 1 for the 4E : CH ratio, and seems otherwise ok.

So:

  3 each of  37 CH commons    111 cards
  2 each of  30 CH uncommons   60 cards
  2 each of 121 4E commons    242 cards
  1 each of 121 4E uncommons  121 cards

  171 CH total
  363 4E total
  534 total spells

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Notes as of 2023-10-22

I'm not sure why I care about the 4E:CH ratio; seems like having the same
number of each commonality of cards would make sense.

I don't seem to have a Mishra's Factory in the box, and Strip mine is a
$10+ card at this time, so I removed it and Oasis as well.